We did a lab in Chem where we put a liquid into a flask, secured foil on the top and poked a hole in the foil so the vapor could push out the air. Then, we heated the flask in boiling water until all the liquid had evaporated. We then let the flask cool and recorded the mass of the condensed vapor. Using this information, we found the molar mass of the liquid.

One of the questions on my lab report is "Was the vapor really 'ideal'? If not, how were your calculations affected? Explain"