Prior Knowledge

Naba and Jannat are conducting an experiment in their chemistry class. They expose red litmus paper to ammonia gas. What happens to the litmus paper?

• It turns red

• It turns blue

• It turns green

• It remains unchanged

What is carbon dioxide used for?

During a science experiment, Innaya and Ayesha were trying to identify a gas produced in a reaction. What test should they use to confirm it's hydrogen gas?

• Use a burning splint

• Use a glowing splint

• Use limewater

• Use litmus paper

Naba and Ayesha were conducting an experiment in their chemistry class. They performed the 'Squeaky Pop Test'. What gas did they use to produce the pop sound?

• Hydrogen gas

• Oxygen gas

• Carbon dioxide

• Nitrogen gas

Hania and Jannat are in the science lab conducting experiments. They want to test for the presence of oxygen gas. What should they do?

• Use a glowing splint; the gas will cause the splint to re-light.

• Use a litmus paper; the gas will turn it blue.

• Use a limewater test; the gas will turn it milky.

• Use a burning candle; the gas will extinguish it.

During a chemistry experiment, Jannat and Ayesha observed that the filter paper wetted with potassium dichromate changes color to ______ when exposed to SO2 gas.

• green

• blue

• red

• yellow

Ayesha and Innaya are conducting a science experiment. They are testing different gases. What observation is made when hydrogen (H₂) is tested?

• 'pops' with a lighted splint

• 'glows' with a lighted splint

• 'fizzes' with a lighted splint

• 'burns silently' with a lighted splint