A sealed 8.00 L vessel at 400 K contains a gaseous mixture composed of 2.00 mol of…
CHEMISTRY · Multi-part · AP · Chemistry · Properties of Substances and Mixtures · Properties of Substances and Mixtures
Problem
A sealed 8.00 L vessel at 400 K contains a gaseous mixture composed of 2.00 mol of neon (molar mass = 20.18 g mol−1) and 1.00 mol of krypton (molar mass = 83.80 g mol−1). The gases do not react and behave ideally.
(a) Calculate the rms speed of a neon atom at 400 K.
(b) Calculate the rms speed of a krypton atom at 400 K.
(c) Determine the mole–fraction–weighted average rms speed of the gas mixture.
(d) Compare the value obtained in part (c) with the rms speed that would be predicted if one first computed an average molar mass for the mixture and then used that single molar mass in the rms speed calculation. Explain any discrepancy, referencing the underlying statistical interpretation of rms speed in a mixture of gases.