Unit 2 (c) - Gases in the Atmosphere

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

• Turns from white to blue.

• Turns from colourless to milky.

• The carbon dioxide bubbles give a squeaky pop sound.

• It freezes.

What colour does sulfur burn in oxygen?

• Blue

• White

• Orange

• Lilac

Which gas makes up approximately 0.9% of dry, unpolluted air?

• Carbon dioxide

• Neon

• Hydrogen

• Argon

What is produced in the thermal decomposition of copper(II) carbonate?

• CuO + H2O

• Cu + CO2

• CuO + CO2

• Cu + O2

What is the appearance of copper oxide?

• White solid

• Colourless gas

• Blue-green liquid

• Black solid

Which of the following has basic character?

• Nitrogen oxide

• Sulfur dioxide

• Magnesium oxide

• Carbon dioxide

How do we solve for the percentage change?

• original quantity - new quantity

• increase ÷ original quantity

• decrease ÷ original quantity

• change ÷ original quantity

NON-CHEMISTRY % CHANGE QUESTION.

In a wetland, 400 birds are observed in 2018 and 450 birds are observed in 2019. Find the percentage change of the no. of birds.

• decreased by 12.5%

• increased by 50

• increased by 12.5%

• increased by 50%

NON-CHEMISTRY % CHANGE QUESTION.

Find the percentage change in the following price reduction:

£45 to £32.85

• 27%

• 73%

• 38%

• 62%

NON-CHEMISTRY % CHANGE QUESTION.

The regular price of a scooter is $65.50. It is on sale for $52.40. What is the percent decrease from the regular price to the sale price of the scooter?

• 35%

• 30%

• 25%

• 20%