Compute the root-mean-square speed of He molecules in a sample of helium gas at a temperature of 105°C.

Answer 1

For this problem, you have to know the equation, which is as follows:

vrms= √(3RT/Mm)

where

R = 8.3145 J /K x mole

T = 273 + 105 = 378 K

Mm = molar mass of gas ( For Helum, Mm = 4.003 g/mol = 4.003 x 10^-3 kg/mol)

vrms= √((3RT)/Mm)= √(3(8.3145J/K∗mol)(378 K))/(4.003×10^-3kg/mol)) = 1534.73 m/sec

To keep sig figs, the answer would be 1.53 x 10³ m/sec.