Gas Reactions and Properties

This lesson covers methods to test for the presence of hydrogen, oxygen, carbon dioxide, ammonia, and chlorine gases in the laboratory. It explains the distinct tests for each gas, such as the squeaky pop test for hydrogen, relighting a glowing splint for oxygen, and turning lime water milky for carbon dioxide. The lesson also discusses the properties of these gases and concludes with a summary of the tests.

Why is it difficult to identify gases based on their appearance?

• Gases are always visible.

• Gases have distinct shapes.

• Gases are often colorless and odorless.

• Gases are usually colorful and have strong odors.

What sound indicates the presence of hydrogen when tested with a lit splint?

• A squeaky pop

• A hissing sound

• No sound

• A loud bang

What happens to a glowing splint in the presence of oxygen?

• It relights

• It changes color

• It extinguishes

• It makes a popping sound

Why does hydrogen produce a pop sound when ignited?

• It is because hydrogen is non-flammable.

• It is a result of a mini explosion.

• It is due to the gas being colorless.

• It is because of the presence of water.

What is the concentration of oxygen in the air?

• 50%

• 75%

• 21%

• 10%

What happens when carbon dioxide is bubbled through lime water?

• The lime water evaporates.

• The lime water turns clear.

• The lime water turns milky.

• The lime water changes to blue.

What color does damp red litmus paper turn in the presence of ammonia?

• Yellow

• Blue

• Green

• Red

What compound forms when ammonia reacts with concentrated hydrochloric acid?

• Ammonium chloride

• Calcium carbonate

• Calcium chloride

• Sodium chloride

What is the effect of chlorine on damp blue litmus paper?

• It turns it yellow.

• It has no effect.

• It turns it red and then bleaches it white.

• It turns it green.

Which gas test involves the formation of a white smoke?

• Chlorine

• Ammonia

• Oxygen

• Hydrogen