4 - Acids and redox

Question 1

strong acid

Answer 1

releases all its hydrogen atoms into solution as H+ ions and completely dissociates in aqueous solution

HCl -> H+ + Cl-

Question 2

weak acid

Answer 2

only releases a small proportion of its available hydrogen atoms into solution as H+ ions

• it partially dissociates in aqueous solution

CH3COOH <-> CH3Coo- + H+

Question 3

base
- classify 3

Answer 3

a compound that neutralises an acid to form a salt
metal oxides
metal carbonates
alkalis

Question 4

give 3 examples of metal oxides

Answer 4

MgO
CaO
CuO

Question 5

3 examples of metal carbonates

Answer 5

Na2CO3
CaCO3
CuCO3

Question 6

what is an alkali
- give 3 examples

Answer 6

it is a base that dissolves in water releasing OH- into solution
NaOH
KOH
NH3

Question 7

what is neutralisation

Answer 7

H+ ions react with a base to form a cat and neutral water

Question 8

acid + metal oxide

Answer 8

salt and water

Question 9

acid + metal hydroxide

Answer 9

salt and water

Question 10

acid + alkali

Answer 10

salt and water

Question 11

ionic equation of acid + alkali

Answer 11

2H+ + O- -> H2O

Question 12

metal carbonates + acid

Answer 12

salt water and CO2

Question 13

How to prepare a standard solution

Answer 13

1) weigh the solid
2) dissolve the solid in a beaker using less distilled water than will be needed to fill the volumetric flask to the mark
3) transfer to volumetric flask and rinse thee beaker with distilled water into the volumetric flask
4)dropwise fill the volumetric flask up to the bottom of the meniscus
5) invert the volumetric flask several times

Question 14

acid-base titration procedure

Answer 14

1) add a measured volume of one solution to a conical flask using a pipette
2) add the other solution to a burette and record the initial burette reading to the nearest 0.05
3) add a few drops of the indicator to the conical flask
4) carry out a trial titration
5) complete the titration each time to the end point - where the indicator changes colour and record the volume needed
6) repeat until concordant results

Question 15

what is oxidation number

Answer 15

the number of e- lost or gained in a chemical reaction

Question 16

ON for uncombined element

Answer 16

0

Question 17

ON combined group 1 element

Answer 17

+1

Question 18

ON combined group 2

Answer 18

+2

Question 19

combined aluminium ON

Answer 19

always +3

Question 20

ON combined flourine

Answer 20

-1

Question 21

Combined oxygen ON

Answer 21

-2

exceptions
-> peroxide it is -1
-> combined with fluorine +2

Question 22

combined hydrogen ON

Answer 22

+1

exception
- when combined with group 1 or 2 metals it is -1

Question 23

combined chlorine ON

Answer 23

• -1

exceptions
- when combined with fluorine and oxygen

Cl2O = +1
ClF2 = +2

Question 24

ON for polyatomic ion

Answer 24

sum of all the ON is equal to he charge of ion

Question 25

ON for compound

Answer 25

the sum of all ON is 0

Question 26

oxidation

Answer 26

gain of oxygen/loss of hydrogen
- or loss of e-

Question 27

reduction

Answer 27

gain of hydrogen/loss if oxygen
- gain of e-