7.1 Air

Question 1

What’s air made up of?

Answer 1

Nitrogen, oxygen, noble gases, water vapour and other gases, carbon dioxide.

Question 2

Give two tests about oxygen in air.

Answer 2

-It relights a glowing splint
-It causes a burning splint to burn more brightly

Question 3

Give two tests about carbon dioxide in air.

Answer 3

-It turns hydrogencarbonate indicator from red to yellow.
-It turns limewater from colourless to milky.

Question 4

Give a test about water and water vapour in air.

Answer 4

-Both turn dry cobalt chloride paper from blue to pink.

Question 5

Give tests about nitrogen and noble gases in air.

Answer 5

There are no simple tests.

Question 6

What’s the order of the color of hydrogencarbonate indicator in ascending order of carbon dioxide?

Answer 6

Purple, red, yellow.

Question 7

What’s the order of the color of hydrogencarbonate indicator in descending order of carbon dioxide?

Answer 7

Yellow, red, purple.

Question 8

The method used to separate the gases in the air is called what?

Answer 8

Fractional distillation.

Question 9

Anhydrous ____ ____ paper can be used to test for the presence of water.

Answer 9

Cobalt chloride