Passage III
Gas effusion occurs when a gas moves through a tiny opening into a region of lower pressure. The rate in milliliters per second (mL/sec) is measured using the apparatus in Figure 1.
A 25 mL gas sample in a syringe freely escapes into a flask. The molecular mass, in a.m.u. (atomic mass units), for seven gases and the time required to completely effuse are recorded in Table 1. The densities (mass/volume) in grams per liter (g/L) and average molecular speed (average distance traveled by a molecule per second) in meters per second (m/sec) are also given.
Figure 2 shows a graph of the effusion rate versus the molecular mass of the gases.
15. What is the relationship between molecular mass and effusion time?
Your Answer is
Correct Answer is B
Explanation
Look at the molecular mass of the substances in table 1 increasing from top to bottom, and the effect time also increases sequentially, which is consistent with option B.