WS 10.8 Worksheet On Solution Concentrations

 

Worksheet 10.8

WORKSHEET ON SOLUTION CONCENTRAT CONCENTRATIONS  IONS  INTRODUCTION

A solution is made up of two parts, the  SOLV  and the SOLUTE . The solution could be  SOLVENT  ENT  and CONCENTRATED or DILUTE .  SOLVENT   SOLVE NT   SOLUTE  CONCENTRATED  DILUTE 

The liquid which dissolves the solute. It is usually water. water. The substance which dissolves - often a solid, but not always. There is a lot of solute and a little water. There is a lot of water and only a little solute.

When we measure out 50cm  of a solution, e.!., hydrochloric acid, we measure out some solventt "water# and some acid to!ether. solven to!ether. In any reactions reactions of the acid, it is the $%l particles which whi ch are involved involved.. The The water is &ust a carrier carrier for the acid, acid, so when when we measur measuree out a volume of the solution, we want to 'now 'now how much acid it contains. To do this, we need to define the CONCENTRATION  of   of the the solutio solution. n. This tells us us how much solute there is in a solution. In chemistry chemistry,, (how much) means means  MOLES   and the ( fixed   fixed volume  of the solution.  volume) is ta'en as * cubic decimetre "*dm #. + *dm is *000cm and is the same volume as * litre./ DEFINITION Co#$e#tr%t&o# o' o' sol(t&o# " +moles ,er m ♦

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#(m*er o' mo moles o' o' sol(te ol(me o' sol(t&o# &# m"

ou must learn this relationship and ou a nd be able to use it and rearran!e it to calc calculate ulate moles of  solute or volume of solution, !iven the other two quantities. 1emember that the volume must be in dm , so convert from cm  if necessary. necessa ry. The units for concentration are mole !e" cu#ic decime$"e which is written mol%dm&' 2ab bottles use the letter M  "meanin!  "meanin! mol(" # and this is the same thin! as mol%dm&'

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3se th 3se thee trian trian!l !lee op oppo posit sitee to he help lp yo you u answ answer er the the ques questi tion onss wh whic ich h fo foll llow ow.. 4ome wor'ed eamples are !iven to help you.

moles o' sol(te $o#$e#tr%t&o# +mol.m!"-

ol(me o' sol(t&o# +m"-

 Ex(m!le)& *+ What is the concentration of a solution which contains 6 moles of copper "II# sulphate in 7dm of solution8 concentration 9 moles ÷ volume 9 6 ÷ 7 9 0.5 mol.  A,) m ol.m m !" -+ $ow many moles of sodium hydroide are there in 600cm  of a solution of concentration 0.6 mol.dm- 8 "1emember that 600cm 9 600 ÷  *000 9 0.6dm#

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Worksheet 10.8  A,) moles 9 concentration × volume 9 0.6 × 0.6 9 0.0/ moles UESTIONS *+ C(lcul($e C(lcul($e $he co,ce,$"( co,ce,$"($io, $io, i, mol%dm mol%dm&' of e(ch of $he followi,. olu$io,)& (+ #+ c+ d+ e+

*0 moles of potassium hydroide in 5dm of solution. *.5 moles of hydrochloric acid in dm of solution. 0.5 moles of calcium chloride in 500cm  of solution. 0.6 moles of sulphuric acid in *00cm of solution. 0.0:5 moles of ma!nesium sulphate in 65cm of solution.

-+ /i,d $he ,um#e" ,um#e" of mole mole of olu$e olu$e i, e(ch e(ch of $he followi,. followi,. olu$io, olu$io,)& )& (+ #+ c+ d+ e+

6dm of 6 mol.dm - nitric acid. 0.65dm of 0.7 mol.dm- ammonium chloride solution. 600cm of 0.; mol.dm- sodium carbonate solution. 70cm of 0.6 mol.dm - hydrochloric acid. 00cm of 7 mol.dm - sodium hydroide solution.

'+ /i,d /i,d $he co,ce co,ce,$" ,$"($i ($io, o, i, mol%dm mol%dm&' of $hee olu$io,)&

In question question ' you have to find the concentration of a solution startin! from a m(  of  solute. The first step is to use the relative formula mass "1# solution.

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Worksheet 10.8 d+ 65cm of 0.05 mol.dm- copper "II# sulphate "%u4> 7# solution. "1A< of %u 9 ?7# e+ *.5dm of 0.7 mol.dm - nitric acid "$> #. "1A< of  9 *7#

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