(Chemistry) Testing Unknown Gases

Question 1

What are the 3 gas tests?

Answer 1

-Carbon Dioxide
-Oxygen
-Hydrogen

Question 2

How do you test for Oxygen?

Answer 2

Method: Use a glowing splint that’s lit and then blown out.

Result: The glowing splint relights (reignites) if oxygen is present.

Oxygen supports combustion.

Question 3

How do you test for Hydrogen?

Answer 3

Method: Hold a lit splint near the mouth of a test tube containing the gas.

Result: A “squeaky pop” sound is heard if hydrogen is present.
.
Hydrogen is highly flammable and explodes when ignited.

Question 4

How do you test for Carbon Dioxide?

Answer 4

Method: Bubble the gas through limewater (saturated calcium hydroxide solution).

Result: The limewater turns milky, cloudy, or chalky if carbon dioxide is present.

Carbon dioxide reacts with limewater to form a precipitate of calcium carbonate (chalk).

Question 5

What is the alternative test to carbon dioxide?

Answer 5

Method: Insert a lit splint into a test tube containing the gas.

Result: The flame will be extinguished if carbon dioxide is present.

This test isn’t reliable since other elements can distinguish fire.