Which of the following gases has the lowest rams velocity at 25°C?
Correct answer: D. Cl2
- A. SO2
- B. N2
- C. O2
- D. Cl2
Explanation
The root-mean-square velocity of a gas is inversely proportional to the square root of its molar mass at a constant temperature. Therefore, the heavier the gas, the lower its rms velocity. In this question, Cl2 has the highest molar mass (approximately 70.9 g/mol), making it the gas with the lowest rms velocity at 25°C. Conversely, N2 and O2 have significantly lower molar masses (28 g/mol and 32 g/mol, respectively), resulting in higher rms velocities. SO2, with a molar mass of 64 g/mol, is also lighter than Cl2, resulting in a higher rms velocity compared to Cl2.
Last updated
About Kinetic Molecular Theory
Kinetic molecular theory explains gases as rapidly moving particles separated by large distances, with negligible volume and negligible intermolecular attraction in the ideal model. It relates temperature to average kinetic energy and explains gas pressure, Boyle's and Charles's laws, diffusion, effusion and the conditions under which real gases deviate from ideal behavior.
Practise Gases
443 free Gases MCQs from Chemistry, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Exams that ask Chemistry questions like this
Chemistry is on 12 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
Related questions
A balloon filled with ethyne is pricked with a sharp pointed needle and quickly dropped in a tank of H2 gas under identical conditions. After a while the balloon will be:
A bottle of dry NH3 and a bottle of dry HCI connected through a long tube are opened simultaneously of both ends. The white NHCl ring formed will be
A fixed mass of an ideal gas is contained in a cylinder at a constant temperature. Now, the pressure of the gas is decreased. What happened to the molecules of gas?
A gas diffuses 1/2 times as fast as hydrogen, its molecular mass is:
A gas sample contains three molecules each having speeds 1 ms-1, 2 ms-1, and 3 ms-1. What is the mean square speed?