C7 acids, bases and salts

Question 1

properties of acids

Answer 1

• soluble in water
• sour to taste
• corrosive

Question 2

properties of bases

Answer 2

• metal oxides, carbonates, hydroxides
• some soluble, called alkalis
• soapy to touch
• corrosive

Question 3

colour of litmus in acid

Answer 3

red

Question 4

colour of litmus in base

Answer 4

blue

Question 5

colour of methyl orange in acid

Answer 5

red

Question 6

colour of methyl orange in base

Answer 6

yellow

Question 7

colour of universal indicator in acid

Answer 7

strong: red
weak: orange/yellow

Question 8

colour of universal indicator in base

Answer 8

strong: purple
weak: blue

Question 9

neutral colour of universal indicator

Answer 9

green

Question 10

reaction between acid and alkali (word equation)

Answer 10

acid + alkali –> salt + water

Question 11

will hydrochloric acid react with metals above or below hydrogen in reactivity series

Answer 11

above

Question 12

metal + acid –>

Answer 12

salt + hydrogen

Question 13

acid + base –>

Answer 13

salt + water

Question 14

acid + carbonate –>

Answer 14

salt + water + carbon dioxide

Question 15

how is a basic oxide formed

Answer 15

when a metal reacts with oxygen

Question 16

is CuO acidic or basic

Answer 16

basic

Question 17

is CaO acidic or basic

Answer 17

basic

Question 18

is Na2O acidic or basic

Answer 18

basic

Question 19

how is an acidic oxide formed

Answer 19

when a non-metal reacts with oxygen

Question 20

is SO2 acidic or basic

Answer 20

acidic

Question 21

is CO2 acidic or basic

Answer 21

acidic

Question 22

describe amphoteric oxides

Answer 22

oxides that react with acids and bases to produce a salt and water

Question 23

list amphoteric oxides

Answer 23

Al2O3
ZnO

Question 24

define salt

Answer 24

• ionic compounds
• made up of cations and anions

Question 25

how to prepare soluble salt by reaction of acid with excess metal/insoluble base/insoluble carbonate

Answer 25

1. warm acid gently (speed reaction)
2. add excess base to acid. ensure all acid neutralised
3. filter to remove excess solid
4. transfer to evaporating dish. evaporate until crystals begin to form
5. leave to cool and filter to get crystals, then dry on filter paper

Question 26

define hydrated substance

Answer 26

substance that is chemically combined with water

Question 27

define anhydrous substance

Answer 27

substance containing no water

Question 28

how to prepare salt by reaction of acid with acid by titration

Answer 28

1. place known volume of acid into conical flast
2. add indicator
3. add alkali to acid until indicator just changes colour
4. record v of alkali added to acid
5. repeat without indicator
6. transfer to evaporating dish. heat to evaporate off some water until crystals form
7. leave to cool, filter to get crystals, leave to dry on filter paper

Question 29

how to prepare insoluble salts

Answer 29

• precipitation
• 2 diff salts in solution mixed together
• produce insoluble salt (ppt) and soluble salt