C4.2.1

Question 1

How do you test for carbon dioxide?

Answer 1

• using limewater (calcium hydroxide)
• the change is caused by the calcium hydroxide reacting with carbon dioxide to form water and a white precipitate of calcium carbonate

Question 2

How do you detect chlorine?

Answer 2

• dissolves in water to form an acidic solution
• bleaches dyes- changes them from coloured to colourless

Question 3

How do you smell substances in the lab?

Answer 3

• chlorine has a “swimming pool” smell
• you cannot inhale a lungful though, as it is toxic

Question 4

How do you detect hydrogen and oxygen?

Answer 4

You use a lit splint then:
- to find hydrogen, it should ignite with a spears pop
You use a glowing splint:
- the splint should relight if oxygen is present