very tough chem question

Question

What is the kinetic energy (in kJ mol-1) of a hypothetical gas with molecular weight 16.2 g mol-1 at a temperature of 48.7 °C? Do not try to identify the gas.

Answer 1

Assume you have 1 mole of the gas.  That would be 16.2 g.

Temperature = 48.7ºC + 273 = 321.7

KE = 3/2 nRT where R = 8.31 J/mol-K and n = moles = 1 

KE = 3/2 (1 mole)(8.31 J/mole-K)(321.7 k) = 4010 J for 1 mole or 4.01 kJ/mole