Diffusion in gases
3 marks · EasyThe table shows how long different gases took to diffuse through air in a set apparatus during an experiment.
| Gas | Time to mix fully (seconds) |
|---|---|
| Hydrogen | 40 |
| Oxygen | 60 |
| Ammonia | 35 |
| Carbon dioxide | 70 |
Which gas diffused the fastest?
Which gas diffused the slowest?
Suggest, using particle ideas, why there is a difference in the speed at which these gases diffuse.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) Ammonia
(b) Carbon dioxide
(c) Lighter gases have particles with lower mass and so move faster, causing them to diffuse more quickly than heavier gases.
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Correctly identifies ammonia as the fastest-diffusing gas based on shortest time.
B1 (b) · 1 mark · Correctly identifies carbon dioxide as the slowest-diffusing gas based on longest time.
M1 (c) · 1 mark · Explains that diffusion rate depends on particle mass (lighter gases move faster).
Worked solution
a) Ammonia (time = 35 s) b) Carbon dioxide (time = 70 s) c) Lighter particles move faster so they diffuse more quickly.