A weather balloon is filled with argon gas (molar mass = 39.95 g mol )
CHEMISTRY · Multi-part · AP · Chemistry · Properties of Substances and Mixtures · Properties of Substances and Mixtures
Problem
A weather balloon is filled with argon gas (molar mass = 39.95 g mol−1). While the balloon is tied down at ground level, the gas is at 300 K. During ascent, solar heating raises the gas temperature to 480 K. The balloon expands but remains spherical, and the argon behaves ideally.
(a) Calculate the rms speed of an argon atom at 300 K.
(b) Calculate the rms speed of an argon atom at 480 K.
(c) Determine the ratio of the rms speeds at 480 K and 300 K, and state the percentage increase in rms speed resulting from the temperature change.
(d) Using kinetic–molecular theory, explain how the change in rms speed you found in part (c) relates to the change in average kinetic energy per mole of argon during the ascent.