DOSEAMENTO DO ÁCIDO ACETILSALICÍLICO NUMA ASPIRINA POR POTENCIOMETRIA E CONDUTIMETRIA

UNIVERSIDADE da MADEIRA

DEPART DEPARTAMENTO AMENTO DE QUÍMICA QUÍMIC A MÉTODOS INSTRUMENTAIS DE ANÁLISE

TRABALHO nº 1

DOSEAMENTO DO ÁCIDO ACETILSALICÍLICO NUMA ASPIRINA POR  POTENCIOMETRIA E CONDUTIMETRIA

Trabalho elaborado por: - Carlos Pestana ( P1-G4 ) - Duarte Correia - Fernanda Freitas - Teresa Chá Chá Realizado a: 13 de Março de 2001

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

ÍNDICE Págs. Resumo

4

Introdução

5

Parte experimental - Resultados experimentais - Tratamento de resultados

11 12 17

Conclusão

35

Bibliografia

37

Apêndices -

Apêndice I

39

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

RESUMO Este trabalho teve por objectivo o doseamento do ácido acetilsalicílico presente numa aspi aspiri rina na.. Para Para tal tal reco recorr rreu eu-se -se a dois dois méto método dos, s, nome nomead adam amen ente te a pote potenc ncio iome metr tria ia e a condutimetria, tendo-se comparado as potencialidades de cada um. Assim para o método potenciométrico, verificou-se que a percentagem do respectivo ácido recorrendo ao método da bissectriz foi 85.53 %; recorrendo à 1ª derivada foi 85.67 %;  pela 2ª derivada 85.53 % e pelo método de Gran foi 85.20 %. Pelo método condutimétrico a  percentagem obtida foi 87.53 % quando na realidade o valor esperado da quantidade de ácido acetilsalicílico na aspirina é 89.96%. Por outro lado, procedeu-se numa primeira etapa à determinação determinação da concentração concentração exacta do KOH (usando o HCl como titulado) recorrendo aos mesmos métodos tendo-se então comparado com o resultado obtido pela padronização com o hidrogenoftalato de potássio.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

INTRODUÇÃO TEÓRICA O doseamento do ácido acetilsalicílico na aspirina pode ser efectuado recorrendo a duas técnicas, a potenciométrica e a condutimetria. Desde longa data, tem-se utilizado a medida de potencial para a determinação dos  pontos finais em numerosas titulações quer de reacções de neutralização como de oxidação –  redução, bem como de precipitação ou complexação.  No caso concreto das curvas de titulação ácido – base, podem obter-se com toda a facilida facilidade de pelo método método potencio potenciométri métrico co sendo sendo particul particularmen armente te útil quando quando se pretende pretende dosear misturas de ácidos (ou bases).[1].  Nas titulações potenciométricas, os potenciais absolutos, ou potenciais em relação a um eléctrodo padrão, não são necessários, e as medidas fazem-se enquanto a titulação vai-se realizando.[2]  Neste tipo de titulação, atende-se as variações de f.e.m. de uma célula electroquímica, à medida que se vai adicionando um reagente de concentração exactamente conhecida à solução em ensaio. O método pode aplicar-se a qualquer reacção titrimétrica, para a qual se disponha de um eléctrodo indicador, que permita seguir as variações da actividade de pelo menos uma, das substâncias intervenientes.[3] Por vezes é conveniente esperar um certo tempo para que o equilíbrio seja atingido, além de que a solução deve ser bem agitada para que fique homogénea. Se mantiver-mos a força iónica constante, por meio de um electrólito suporte o valor  do potencial de junção mantém-se constante durante a titulação, assim como o valor dos coeficientes de actividade das espécies em solução. Nestas condições a forma da curva de titulação vem idêntica, apresentando-se somente deslocada em relação aquela que se obteria   para o caso de não haver potencial de junção e de os coeficientes de actividade sem unitários.[4] O ponto de equivalência será revelado por uma abrupta modificação do potencial no gráfico das leituras da f.e.m. contra o volume da solução titulante. Além de permitir estabelecer o ponto de equivalência equivalência de uma reacção, o método pode, ainda, fornecer informação acerca acerca da amostra e das suas reacções, a partir do registo completo da curva de titulação potenciométrica. As princi principai paiss vanta vantagen genss do método método pot poten encio ciomét métric ricoo resid residem em na sua aplica aplicação ção a soluções turvas, fluorescentes, opacas ou coradas, ou quando não existem, ou não podem aplicar-se indicadores visuais apropriados. O método apresenta, ainda, a possibilidade da dete determ rmin inaç ação ão de um umaa suce sucess ssão ão de pont pontos os de equi equiva valê lênc ncia ia,, na ti titu tula laçã çãoo de dive divers rsos os componentes em mistura. Próximo do ponto de equivalência, a concentração de reagente original torna-se muito  pequena e é normalmente impossível para o ião, ou iões, controlar o potencial potencial do eléctrodo. A força electromotriz da célula torna-se instável e indefinida porque o eléctrodo indicador não mergulha em quantidades suficientes da cada espécie do par redox em estudo. Se as espécies não estão demasiado diluídas, uma gota, ou duas, de titulante será suficiente para que se ultrapasse o ponto de equivalência e se passe para a zona estabilizada das espécies do par  redox do titulante. Soluções mais diluídas que 10 -3 ou 10-4 M não conduzem, em geral, a  pontos satisfatórios.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

da primeira derivada assim obtida corresponde ao ponto de inflexão da curva de titulação original como se mostra na figura 2.[4]

Figura 2 - Curva da primeira derivada da titulação potenciométrica [5] Uma vez conhecido o ponto final, a força electromotriz da célula correspondente a este  ponto pode obter-se a partir da curva de titulação original. Pode-se ainda, obter o termo do ensaio de forma mais precisa, à custa da “segunda deri deriva vada da”, ”, cuja cuja curv curvaa é traç traçad adaa toma tomand ndoo em orde ordena nada dass o coci cocien ente te entr entree a razã razãoo dos dos increment incrementos os da f.e.m. f.e.m. e volume volume ( fem/ V ) e o iincrem ncremento ento V, contra contra o volume volume de titul titulante ante adicionado, em abcissas. No termo do ensaio, a Segunda derivada torna-se numericamente igual a zero, ao mesmo tempo que se dá a brusca mudança de sinal da ordenada.[3]

Figura 3 - curva da Segunda derivada da titulação potenciométrica [5] Como a localização do ponto final não envolve os erros pessoais que entram na mudança de cor de um indicador, as titulações potenciométricas constituem um dos métodos analíticos mais exactos e de maior rigor. Porem, este rigor é obtido à custa de uma maior  complexidade e perda de tempo.[4]  Numa titulação potenciométrica ácido – base, para a determinação de constantes de estabilidade, portanto em que se necessita de uma maior precisão, faz-se primeiro uma titulação ácido forte – base forte usando como eléctrodo indicador o vidro e de referencia o saturado de calomelanos para determinar a concentração do titulante. O potencial potencial medido é: Ecel = Evid – Eref  + E j = K – 0.0591 pH ( a 25ºC )

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

Sendo Ca, Va, respectivamente, a concentração e o volume da solução do ácido, adicionado, C b, V b, os valores respectivos para a base e V0 o volume de solução inicial a titular.  No ponto de equivalência equivalência : CaVa = C bV b  pelo que

[ H + ] = C b

Ve - V b V0 − V b

Explicando o valor de [H +] da equação de Nernst e substituindo na equação anterior, vem (V0 + V b )10 (E −K)/59,15 = C b (Ve − V b ) onde Ve é o volume de base correspondente correspondente ao ponto de equivalência equivalência e o potencial exprime-se exprime-se em milivolts. Se arbitrarmos um valor para K e representarmos (V 0+V b)10(E-K) /59,15 em função de V b, a intersecção da recta com o eixo dos V b dá o valor de V e. Assim se pode saber a concentração de um dos reagentes (sabendo a do outro) e  portanto determinar :

[H + ] = C

a

Va V0

−C V +V  b

 b

 b

Para os vários pontos da curva de titulação, o que permite calcular E-59,15log[H +] = K para cada ponto, achando como valor mais provável o valor médio. Este é o método de Gran, em que uma vez determinado o valor de K para o par de eléctrodos considerado, podem determinar-se valores de pH em titulações ácido fraco – base forte, ou complexométricas e calcular constantes de estabilidade. O movimento de iões em solução permite a passagem de corrente eléctrica através da variação da condutibilidade duma solução ( ou da sua resistência ) pode-se, por exemplo, determinar a curva de titulação, desde que o número de tipo de iões varie à medida que se

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

número igual de iões M + de menor condutividade. Este é o princípio básico das titulações condutimétricas, ou seja, a substituição de iões, que têm uma certa condutividade por outros iões de outra condutividade. Depois do ponto de equivalência, contudo, contudo, como se adiciona um excesso de M + e OH-, a condutividade começa de novo a aumentar antes do ponto de equivalência a condutividade vem dada pela seguinte expressão : 1 A = ( C + λ  + + C M+ λ M + + C X − λ X− ) R  1000d H H Se a solução inicial tem um volume de V a mL e a concentração de C0a equivalentes equivalentes de ácido  por litro e se f é a fracção de ácido neutralizado pela adição de V  b mL de MOH, então :

  Va        Va + V b     Va     = C a0     Va + V b     Va     = fC a0     Va + V b  

C H + = (1 − f ) C a0  C X− C M+

Portanto, até ao ponto de equivalência : 1 AC a0   Va      = [(1 − f ) λ H + + fλ M+ + λ X− ] R  1000d  Va + V b     ou 1 AC a0   Va     [ λ H+ + λ X − + ( λ M+ − λ H+ )f ] = R  1000d   Va + V b     Esta equação tem a forma :

  1    Va + V b   = K 1 - K 2 f  R   V    

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

onde C b é a concentração da base. Aplicando de novo a equação que estabelece a relação entre a condutividade da solução e a condutividade equivalente dos vários iões, para este caso, vem

 C b 1  Va + V b   A  0    = − + + C ( λ  λ  ) ( λ  λ  ) V − − + −  a X  b  OH OH R   Va   Va M   1000d   que é da forma

 V + V  R    V 1

a

 b

a

     = −K  + K  V   3

4

 b

λ  + λ   pois que OH é sempre maior do que X - . Depois do ponto de equivalência, portanto, uma 1 Va + Vb representação gráfica de × em função do volume de reagente usado será uma R  Va linha recta, mas de coeficiente angular positivo. Assim se verifica que a curva de titulação será em forma de V e o ponto de equivalência estará no ponto de intersecção das duas rectas.[C]

Figura 4 – Curva de titulação condutimétrica ácido forte - base forte.[4] Em contraste com o método potenciométrico, a medição nas vizinhanças do ponto de equivalência não têm significado especial. Porém na titulação de um ácido fraco com uma base forte, origina uma espécie de curva

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

maior do que o simultâneo crescimento de C M + λ M + e C X - λ X - e a condutibilidade total da solução diminui. Contudo, posteriormente a concentração hidrogeniónica diminui para um valor tão baixo que a sua contribuição para a condutividade da solução ( que agora contém uma concentração relativamente relativamente grande de M + e X - ) é desprezável. Então, a neutralização de uma maior fracção de ácido provoca somente um aumento no numero de iões M + e X - e assim a condutividade aumenta. A condutividade passa por um mínimo e depois começa de novo a aumentar, aumentar, antes de se ter atingido o ponto de equivalência e a curva de titulação assemelha-se a uma das curvas da figura seguinte.[4]

Figura 5 - Curvas de titulação condutimétrica de vários ácidos fracos com uma base forte.[4] A grande vantagem dos métodos condutimétricos é que estes podem ser aplicados onde os métodos visuais ou potenciométricos não dão resultados satisfatórios em virtude da solubilidade considerável, ou da hidrólise considerável, no ponto de equivalência [2]

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

PARTE EXPERIMENTAL EXPERIM ENTAL Material utilizado -

Espátula Vareta Gobelets Balã Balãoo vol volum umét étri rico co de 250 250 mL mL Pipetas graduadas Suporte universa rsal Garras Agitador ma magnét nético Plac Placaa de de agi agita taçã çãoo mag magné néti tica ca Pipetas Pasteur 

Equipamento específico -

Apare Aparelho lho medido medidorr de pH ( Metro Metrohm hm 620 pH-met pH-meter er ) Eléctrodo de vidro Aparelho Aparelho medidor medidor de cond condutân utância cia (Crison (Crison microC microCM M 2200) 2200) / célul célulaa condut condutimétr imétrica ica Balança analítica

Reagentes e soluções -

Hidr Hidrog ogen enof ofta tala lato to de de pot potás ássi sioo (KHP (KHP)) Solu So luçã çãoo de hid hidró róxi xido do de de potá potáss ssio io 0.1 0.100 00 N Solu So luçã çãoo de de áci ácido do clor cloríd ídri rico co 0.01 0.01 N Aspirina Água de destilada

Procedimento Procedimento experimental

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE ()

A solução de aspirina ficou turva por conter um excipiente.

RESULT RESULTADOS EXPERIMENTAIS EXPERIM ENTAIS   Numa Numa primei primeira ra etapa etapa,, proced procedeueu-se se à padron padroniza izaçã çãoo do hid hidróx róxid idoo de pot potás ássio sio com Hidrogeno Hidrogenoftal ftalato ato de potássio potássio tendo-se tendo-se registado registado os seguinte seguintess valores valores que se encontram encontram descriminados na seguinte tabela

Tabela 1 –  Valores relativos à padronização do hidróxido de potássio Massa de KHP (g) 0,2093 0,2075

Volume de KOH ( mL ) 12,10 11,90

Posterio Posteriorment rmente, e, procedeuprocedeu-se se à titu titulaç lação ão potencio potenciométri métrica ca do ácido ácido clorídri clorídrico co com o hidróxido de potássio, tendo-se obtido valores de pH para cada volume de base adicionado à solução titulada , e que se apresentam na seguinte tabela .

Tabela 2 –  Valores de pH obtidos durante a titulação potenciométrica potenciométr ica da solução de HCl 0.01 N com KOH 0.100 N.

Volume de KOH ( mL )

PH

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

5,4 5,5 5,6 5,7 5,8 5,9 6,0 6,5 7,0 7,5 8,0 8,5 9,0 9,5 10,0

9,78 9,99 10,16 10,28 10,35 10,46 10,53 10,63 10,80 10,95 11,05 11,13 11,20 11,27 11,32

De uma forma semelhante procedeu-se á titulação condutimétrica do ácido clorídrico 0.010 N com o hidróxido de potássio 0.100 N, obtendo-se desta forma os valores de condutibilidade após a adição da respectiva base à solução titulada. Os resultados encontramse discriminados na seguinte tabela.

Tabela 3 –  valores obtidos durante a titulação condutimétrica do HCl 0.001 N com o KOH 0.100 N. Volume de KOH ( mL ) 0,0

Condutividade ( S cm-1 ) 1285

Condutância ( S) 1179

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

6,5 6,7 7,1 7,6 8,1

562 593 610 637 678

516 544 56 0 584 622

Analogamente, procedeu-se à titulação potenciométrica do ácido acetilsalicílico com o hidróxido de potássio tendo-se obtido os resultados que se encontram na seguinte tabela.

Tabela 4 - Dados referentes à titulação potenciométrica do ácido acetilsalicílico com o KOH. Volume de PH KOH ( mL ) 0,0 2,84 0,5 2,87 1,0 2,99 1,5 3,00 2,0 3,05 2,5 3,11 3,0 3,18 3,5 3,22 4,0 3,28 4,5 3,33 5,0 3,40 5,5 3,46 6,0 3,51 6,5 3,57

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

12,4 12,5 12,6 12,7 12,8 12,9 13,0 13,3 13,5 13,7 13,9 14,1 14,3 14,5 15,0 15,5 16,0 16,5 17,0 17,5 18,0 18,5 19,0 19,5 20,0 2,05 2,10

5,09 5,23 5,46 5,76 6,46 7,91 9,56 10,03 10,25 10,39 10,51 10,59 10,66 10,73 10,85 10,99 11,07 11,14 11,20 11,25 11,31 11,35 11,38 11,42 11,45 11,47 11,50

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

5,5 6,0 6,5 7,0 7,5 8,0 8,5 9,0 9,5 10,0 10,5 10,6 10,8 11,0 11,2 11,4 11,6 11,8 12,0 12,2 12,4 12,6 12,8 13,0 13,2 13,4 13,5

361 364 376 388 400 422 432 453 461 480 496 496 504 509 516 520 526 535 535 547 550 559 566 576 588 611 616

331 334 345 356 367 387 396 416 423 44 0 455 455 462 467 473 477 483 491 491 502 505 513 519 528 539 561 565

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

TRAT TRATAMENTO DOS RESULT RESULTADOS EXPERIMENTAIS EXPERIM ENTAIS Determinação da concentração exacta do KOH com o objectivo de determinar a concentração exacta do KOH, recorreu-se a alguns métodos distintos. Assim, recorrendo aos resultados experimentais obtidos temos.

Pelo método do padrão primário A concentração do KOH obtida através do padrão primário é obtida por métodos visuais, isto é, recorrendo a uma solução de Hidrogenoftalato de potássio na presença de indicador  fenoftaleína. Uma vez que no equilíbrio: n n a = n b C= e V Então :

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

A curva de titulação segundo o método potenciométrico, é dada pela representação dos valores de pH vs V KOH obtidos experimentalmente e apresentados na tabela 2. Desta forma para a obtenção da concentração de KOH temos de determinar o ponto final que graficamente representa o ponto de inflexão da curva ,como se pode constatar no seguinte gráfico. Gráfico 1 – Curva da titulação potenciométrica do HCl com o KOH

12 10 8

   H 6   p 4 2

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

0,1 0,1 0,1 0,1 0,1 0,1 0,1 0,1 0,1 0,1 0,1 0,1 0,1 0,1 0,1 0,1 0,1 0,5

0,09 0,10 0,09 0,11 0,14 0,20 0,35 1,23 1,49 2,46 0,41 0,21 0,17 0,12 0,07 0,11 0,07 0,10

4,35 4,45 4,55 4,65 4,75 4,85 4,95 5,05 5,15 5,25 5,35 5,45 5,55 5,65 5,75 5,85 5,95 6,25

0,90 1,00 0.90 1,10 1,40 2,00 3,50 12,3 14,9 24,6 4,10 2,10 1,70 1,20 0,70 1,10 0,70 0,20

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

O máximo da curva da primeira derivada corresponde ao ponto de inflexão na curva de titulação pelo que o volume de titulante adicionado corresponde ao volume no ponto de equivalência. O volume obtido da representação gráfica foi 5.20 mL.

Recorrendo Recorrendo à curva da 2ª derivada Uma outra forma de se obter o ponto final com uma precisão elevada é recorrendo à curva da segunda segunda derivada. Para tal tal é necessário necessário derivar-se derivar-se a curva curva pH/ V = f(V) f(V) e os dados dados  para a representação encontram-se na seguinte tabela.

Tabela 7 –  Valores necessários para a representação gráfica da segunda derivada. Vm* 0,5 1,0 1,5 2,0 2,5

2

pH/ 2V 0,16 -0,08 0,08 0,00 0,08

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

Tendo em conta estes valores temos a seguinte representação gráfica. potenciométrica do HCl com KOH Gráfico 3 – Curva da 2ª derivada relativa a titulação potenciométrica

150 100    )    1   -

   L   m    (

   V    2

50 0

   / -50    H   p    2 -100

-150 -200 -250

0

2

4

6

8

10

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

4,6 4,7 4,8 4,9 5,0 5,1 5,2 5,3 5,4 55

3,39 3,5 3,64 3,84 4,19 5,42 6,91 9,37 9,78 9 99

0,0630 0,0489 0,0355 0,0224 0,0100 0,0006 1,91E-05 6,62E-08 2,58E-08 1 59E 08

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

 Nesta  Nesta situação, situação, temos por extrapola extrapolação ção do gráfico que o vol volume ume de titulan titulante te gasto quando estamos em condições de equilíbrio ( ponto de equivalência ) é 5.13 mL.

Método condutimétrico Pelo método condutimétrico, podemos também determinar a concentração do KOH tendo em conta as medidas de condutibilidade efectuadas efectuadas durante a titulação. titulação. Assim, uma vez -1 que que a cons consta tant ntee de cél célula ula é 1.09 1.09 cm e consi consider derand andoo os valor valores es de condu condutib tibili ilidad dadee apresentados apresentados na tabela 3 determinou-se determinou-se os valores de condutância. condutância. Efectuando Efectuando a correcção

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

Representando graficamente a variação da condutância já corrigida com o volume de KOH adicionado, obtemos o seguinte gráfico.

Gráfico 5 –  Variação da condutância corrigida com o volume de titulante para a titulação condutimétrica do HCl

1400

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

Tabela 10 –  Resultados obtidos para a concentração do KOH, recorrendo aos diferentes métodos. Método Padrão primário (KHP) Bissectriz 1ª derivada Potenciométric o 2ª derivada G áfi d G

Volume de titulante (mL) 5.17 5.18 5.19 5 13

[KOH] (M) 0.08484 0.09671 0.09653 0.09634 0 09747

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

recorrendo à curva da 1ª derivada Para operar este método é necessário obter-se os valores relativos a pH e V de forma a se poder poder calcu calcular lar pH/ V e o V médio. Desta forma construiu-se a seguinte tabela.

Tabela 11 –  valores necessários para a representação gráfica da primeira derivada V 0,5

pH 0,47

Vm 0,25

pH/ V 0,94

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

01

1 45

12 85

14 50

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

O ponto de equivalência dado pelo máximo da representação corresponde ao volume de

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

Curva da 2ª deriv derivada ada relati relativa va a titula titulação ção pot potenc encio iomét métric ricaa do ácido ácido Gráfico 8 –  Curva

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

85

3 84

1 23E 03

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

MÉTODOS INSTRUMENTAIS DE ANÁLISE

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.