Water and Gases

Question 1

(1) Water

Add to anhydrous copper(II) sulfate

Answer 1

White copper(II) turns blue

Question 2

(2) Water

Add to anhydrous cobalt(II) chloride

Answer 2

Blue cobalt(II) chloride turns pink

Question 3

(1) Gases - Carbon dioxide

Pass through limewater (calcium hydroxide solution)

Answer 3

Limewater changes from colourless to milky

If carbon dioxide is in excess, the milky ppt redissolves to give a colourless solution

Question 4

(2) Gases - Hydrogen

Put a burning splint into a sample of the gas

Answer 4

Splint burns with a squeaky pop

Question 5

(3) Gases - Oxygen

Put a glowing splint into a sample of the gas

Answer 5

Glowing splint relights

Question 6

(4) Gases - Chlorine

Damp universal indicator paper or damp litmus paper

Answer 6

Turns (or remains) red

Then bleaches

Question 7

(5) Gases - Sulfur dioxide

Filter paper dipped in acidified potassium dichromate(VI) solution

Answer 7

Orange to green

Question 8

(6) Gases - Ammonia

a) Damp universal indicator paper
b) Glass rod dipped in concentrated hydrochloride acid

Answer 8

a) Turns blue

b) White fumes

Question 9

(7) Gases - Hydrogen chloride

a) Damp universal indicator paper
b) Glass rod dipped in concentrated ammonia solution

Answer 9

a) Turns red

b) White fumes