Analysing techniques - testing gases

Question 1

What apparatus do you need to test for hydrogen gas?

Answer 1

• Test tube of dilute hydrochloric acid and zinc
• Boiling tube
• Splint
• Bunsen burner

Question 2

What safety precautions do you need to take when testing for hydrogen?

Answer 2

Wear eye protection. Hydrogen gas is flammable.

Question 3

What steps need to be taken when testing for hydrogen?

Answer 3

1. Record your observations when you hold a lighted splint at the open end of the test tube of hydrogen gas.
2. Explain your observations.
3. What do the methods of collecting hydrogen gas tell you about its properties?

Question 4

What observation will we make for a positive test for hydrogen?

Answer 4

A lighted splint ‘pops’

Question 5

What steps need to be taken to test for oxygen?

Answer 5

1. Collect 15cm*3 hydrogen peroxide solution in a small conical flask.
2. Add a small amount of manganese oxide from the end of a spatula.
3. Insert a glowing splint (made by blowing out a lighted splint) in the mouth of the flask.
4. Record and explain your observations.

Question 6

What safety precautions do we need to take when testing for oxygen?

Answer 6

Wear eye protection

Question 7

What observation will we make if oxygen is present?

Answer 7

A glowing splint relights

Question 8

What is the hydrogen test called?

Answer 8

Squeaky pop test.

Question 9

What is the oxygen test called?

Answer 9

Relighting splint test

Question 10

What is the carbon dioxide test called?

Answer 10

Limewater test

Question 11

What apparatus do you need to test for carbon dioxide?

Answer 11

• Marble chips
• Dilute hydrochloric acid
• Limewater
• Test tube with cork and glass tube
• Another test tube

Question 12

What is the objective of the limewater test?

Answer 12

To bubble carbon dioxide gas through limewater (calcium hydroxide solution) using the apparatus.

Question 13

What observation will we make if carbon dioxide is present?

Answer 13

The limewater turns milky (cloudy white)

Question 14

What type of gas is chlorine?

Answer 14

A toxic gas

Question 15

What are the steps taken to test for chlorine gas?

Answer 15

1. Concentrated hydrochloric acid (corrosive) will be added to a spatula of moistened potassium manganate crystals in a boiling tube held in a rack inside a fume cupboard.
2. A piece of damp blue litmus paper can be held in
   the mouth of the boiling tube.

Question 16

What observation will we make if chlorine gas is present.

Answer 16

The damp blue litmus paper turns white (as it gets bleached)