States of Matter 1 Question 46

46. If a gas is expanded at constant temperature

(1986, 1M)

(a) the pressure decreases

(b) the kinetic energy of the molecules remains the same

(c) the kinetic energy of the molecules decreases

(d) the number of molecules of the gas increases

Numerical Value Based Question

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Solution:

  1. Pressure is inversely proportional to volume at constant temperature, hence (a) is correct.

Average kinetic energy of a gas is directly proportional to absolute temperature, hence (b) is correct.

Expansion at constant temperature cannot change the number of molecules, hence (d) is incorrect.