0.325g sample of gaseous hydrocarbon (consists of carbon and hydrogen only), occupies
A volume of 193mL at 749mmHg and 26.1ºC. Determine the molecular mass, and draw a plausible Lewis structure for this hydrocarbon

My question about this question what is
"a volume of 193mL at 749mmHg and 26.1ºC"

Other things I know how to do.. I just did not understand..

susus
The numbers you have been given are the variables in the Ideal Gas Law (which is given in the question preceding yours). You have been given the volume and temperature - surely you recognise them; mmHg is the pressure of the gas in millimeters of mercury. Solve for moles, that will give you the Mol. Wt.
There you go.