Chemistry Form 4 Definition List

c
 
  1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36.

Ú

 ± a substance consists of one type of atom.  ± a substance consists two or more types of elements that are chemically bondedtogether(Ê

   . J ± smallest neutral particle of an element.




 Ú

±a neutral particle consists of similar non-metal atoms which are covalently-bonded.




  a neutral partical consists of different non-metal atoms which are covalently-bonded.  ± Positively or negatively charged particles which are formed from metal or non-metal atom. - It occurs when particles of a substance move between the particles of another substance. 
 ± atoms of the same element with same proton number but different nucleonnumbers. 

   


 ±RAM based on carbon-12 scale is the mass of one atom of the element compared with 1/12 of the mass of an atom of carbon-12. 


    


 = the average mass of one atom of an molecule/((1/12 x the mass of one carbon-12 atom

   Molar mass is the mass of one mole of any substance.

   
    Volume occupied by one mole of any gas is 24dm^3 at room temperature and 22.4 dm^3 at STP.


    ± Molecular formula is the formula that shows the actual number of atoms of each element that are present in a molecule of the compound. Ú   ± Empirical formula is the formula that shows the simplest whole number ratio of atoms of each element in the compound.


± Mole is an amount of substance that contains as many particles as the number of atoms inexactly 12 g of carbon-12.( the symbol of mole is mol. 

± Avogadro constant ± 6.02 x 1023  ( 
 ±The vertical column of elements in the Periodic Table arranged according to the number of valence electron in the outermost occupied shell are called groups. 
 ( 
 ± The horizontal row of elements in the Periodic Table, consist of the same number of shells occupied with electron in an atom are called period. 



 ± electrons that occupy the outermost shell. Ú

-Tendency of the atom to receive electron to form negatively charged ion. Ú
-Tendency of the atom to release electron to form positively charged ion.  !
-Basic oxide is metal oxide that can react with acid to form salt and water. (Na,Mg J  !
-Acidic oxide is non metal oxide that can react with alkali to form salt and water. (Si,P,S,Cl J"
 !
-Amphoteric oxide is oxide that can react with both acid and alkali to form salt and water. (Al  # ± Formed when positive ion from metal atom and negative ion from non-metal atom is attracted by strong electrostatic forces.   ± consist of positive ions and negative ions which are held by strong electrostatic forces of attraction. 
 # ± Formed when two or more similar or different non-metal atoms share valence electrons between them so that each atom achieves stable electron arrangement. 
  (also simple molecular structure ± consists of neutral molecules which are held by weak intermolecular forces (Ñ  
.  Element that can conduct electricity at solid or molten state without any chemical changes occur to it. Ú
 
Compounds that can conduct electricity in Ê
 state or   solution and undergo chemical changes.  Ú
 
Compounds that cannot conduct electric current in any state. Ú
 Electrolysis is a process whereby an electrolyte is decomposed to its constituent elements when electric current passes through it. Ú
  
An electrolytic cell is a set up apparatus that contains two electrodes which are dipped in an electrolyte and produce a chemical reaction when connected to a battery(source of electricity. J
An electrode that is connected to the positive terminal of the battery in an electrolytic cell . "
An electrode that is connected to the negative terminal of the battery in an electrolytic cell. JNegative ions that are attracted and move to the positive charged electrode(Anode.

3
Positive ions that are attracted and move to the negative charged electrode(Cathode. 3

 Ú

An electrode that acts as a conductor only and does not undergo chemical changes.(carbon,platinum,graphite 3


Ú

An electrode that not only acts as a conductor but also undergoes chemical changes.(copper,silver,nickel $%
Ú
"
 &

Electrochemical series is an arrangement of metals according to their tendency to release electrons to form a positive charged ion. $'

  

 
The metal which is situated at a higher position in the electrochemical series is able to displace a metal below it from its salt solution. $(
  
A cell that produces electrical energy when chemical reactions occur in it. 43. J )  (base ±Alkali is a base which is soluble andionises in water to produce hydroxide ions, OH-. 44. J ± chemical substance which ionises in water to produce hydrogen ions, H+. 45.     -Basicity of an acid is the number of ionisable of hydrogen atom per molecule of an acid molecule is an aqueous solution. 46. 
-Bases is a chemical substance that reacts with acid to produce salt and water only.

47. * ±ph is a scale of numbers to measure the degree of acidity or alkalinity of an aqueous solution based on the concentration of hydrogen ions,H+ or hydroxide ions,OH- . Scale ranges from 0 to 14. 48. &  )  ± strong alkali is an alkali that ionises completely in water to produce high concentration of hydroxide ion, OH-. 49. +
)  )  ± Weak alkali is an alkali that partially ionises in water to produce low concentration of hydroxide ion, OH-. 50. &  ± strong acid is an acid that ionises completely in water to produce high concentration of hydrogen ion, H+. 51. +
)  ±Weak acid is an acid that partially ionises in water to produce low concentration of hydrogen ion, H+. 52. &  ± solution is a homogeneous mixture formed when a solute is dissolved in a solvent. 53.  -Molarity is the concentration of solution. (g dm-3 / mol dm-3. 54. &  &  ± standard solution is a solution that its concentration is accurately known. 55.  
 - Neutralisation is the reaction between an acid and a base to form only salt and water. 56. &  ± Salt is a compound formed when the hydrogen ion in an acid is replaced with metal ion or ammonium ion. 57. , 
J  ± Qualitative analysis of a salt is a chemical technique to identify the ions present in a salt. 58. J  ± Alloy is a mixture of two or more elements with a certain fixed composition. The major component in the mixture is a metal. 59.  
 ±Polymer is a long chain molecules made up of many identical number of small repeating sub-unit called monomer. 60. 

  ± Composite materials are structural materials that are formed by combining two or more different substances such as metals, alloys, glass, ceramics, and polymers.

V V

Ô

 













3
3
      


V