Question

A 200.0 mL sample of a noble gas collected at 78.5 kPa and 10°C has a mass of 0.027 g. What is the molar mass of the gas? Identify the sample.

Answer 1

PV = nRT.

Substitute the numbers and solve for n = number o fmols.
\Then mols = g/molar mass. You know grams and mols, solve for molar mass. If you use 78.5 kPa for P then use 8.314 for R. Remember to convert T to Kelvin. Kelvin temperature = 273 + degrees C.
Post your work if you get stuck.