C4.2.1 - Detecting Gases

Question 1

What do you use to detect carbon dioxide?

Answer 1

Limewater

Question 2

What is limewater?

Answer 2

A calcium hydroxide solution

Question 3

What happens to limewater when carbon dioxide is bubbles through it?

Answer 3

It turns cloudy white

Question 4

What is formed when calcium hydroxide reacts with carbon dioxide?

Answer 4

Water

White precipitate of calcium carbonate

Question 5

Why does limewater turn cloudy white when carbon dioxide is bubbled through it?

Answer 5

The reaction between calcium hydroxide and carbon dioxide creates a white precipitate which changes the colour

Question 6

What forms when chlorine dissolves in water?

Answer 6

An acidic solution

Question 7

Describe the chlorine test.

Answer 7

Dampen a piece of blue litmus paper. Hold the litmus paper above the solution. If the litmus paper turns red then white, then chlorine is present

Question 8

How do you test for hydrogen?

Answer 8

Hold a lit splint by the gas. If the splint extinguishes with a squeaky pop, then hydrogen gas is present

Question 9

How do you test for oxygen?

Answer 9

Hold a glowing splint near the gas. If the splint reignites, then oxygen is present

Question 10

Why must you be careful when inhaling substances?

Answer 10

They can be harmful or toxic

Question 11

Describe how you should smell a substance?

Answer 11

Hold the solution away from your nose. Fill most of your lungs, and slowly waft the smell towards you. Take a cautious sniff, so you do not inhale too much