Measuring gases: Introduction

Water in the atmosphere is a greenhouse gas.

• True

• False

Which of the following statements relating to the kinetic molecular theory of gases is INCORRECT.

1. 1. Gas particles move at random and collide elastically.

2. 2. The volume of gases is mostly empty space.

3. 3. The forces of attraction and repulsion between gas particles are practically zero.

4. 4. The speed with which gas particles move remains constant as temperatures change.

• 1

• 2

• 3

• 4

More molecules close together, means density is:

• high
• low

An object should float in a liquid if it is 

• Denser than the liquid 
• Less dense than the liquid
• Lighter than metal
•  Shaped like a ball 

Which type of radiation from the Sun causes the greenhouse effect?

• 
  Visible light

• 
  Ultraviolet

• 
  Infrared

• Gamma rays

Answer explanation

Water vapour, carbon dioxide and other greenhouse gases can absorb and radiate back infrared radiation, contributing to the greenhouse effect.

Which of the following is not a greenhouse gas?

• 
  Water vapour

• Oxygen

• 
  Methane

• 
  Carbon dioxide

Answer explanation

Carbon dioxide, CO₂, methane, CH₄, and water vapour, H₂O, are all classified as greenhouse gases; that is, they are gases that absorb infrared radiation and, hence, contribute to the greenhouse effect.

Which of these would be considered to be evidence of climate change?

• The average rainfall in Townsville varies from one month to the next.

• Experts estimate that nearly 3 billion animals were displaced or killed in Australia’s 2019–2020 bushfires.

• 
  Tasmania has a completely different climate from that of Brisbane.

• 
  Australia’s climate has warmed by an average of >1 °C since records began in 1910.

Answer explanation

Australia’s climate has warmed by an average of >1 °C since records began in 1910.

Plants absorb _______ during photosynthesis.

Deforestation results in a net ______ in greenhouse gases.

Water vapour is the most abundant greenhouse gas on Earth. It efficiently traps heat to warm the atmosphere.

When global temperatures increase, more liquid water evaporates to form water vapour.

The amount of heat-trapping water molecules increases, further increasing temperature.

Which of the following properties of water allows it to have this effect?

• Density

• Solubility

• Specific heat capacity

• Boiling point