Molecular speeds: An ideal gas is kept in a rigid container that expands negligibly when heated. The gas starts at a temperature of 20.0°C, and heat is added to increase its temperature. At what temperature will its root-mean-square speed (thermal speed) be double its value at 20.0°C?
A) 40.0°C
B) 141°C
C) 313°C
D) 400°C
E) 899°C

Question

Quizplus · Accepted Answer

The root-mean-square speed of a gas is proportional to the square root of its absolute temperature (Kelvin). To double the speed, the temperature must be quadrupled. Starting from 293 K (20°C), quadrupling gives 1172 K, which is 899°C.

Molecular Speeds: an Ideal Gas Is Kept in a Rigid