IB myp 4-5 Chemistry – Practice Questions- All Topics
Topic :Matter-Diffusion
Topic :Matter- Weightage : 21 %
All Questions for Topic : states and properties of matter,particle/kinetic theory,diffusion,atomic structure [including isotopes],electron configuration and valency
Question : Matter – Gas Laws & Diffusion
Question a [3 marks]
Explain why helium diffuses through a balloon’s membrane faster than air at the same temperature.
▶️ Answer/Explanation
• Air is mostly N2 and O2 (larger molecules)
• He atoms are smaller/lighter than air molecules
• He moves faster at same temperature
Question b [4 marks]
Explain why hot air balloons rise in terms of gas behavior.
▶️ Answer/Explanation
• Hot air has greater kinetic energy
• Same mass occupies larger volume
• Density decreases compared to cold air
• Lower density causes upward buoyant force
Question c [2 marks]
Describe what happens to a sealed bag of air when external pressure decreases.
▶️ Answer/Explanation
• Bag expands/inflates
• Internal pressure remains constant
• Volume increases as external pressure decreases