A scientist isolated 3.621g of a gas. The sample occupies a volume of 975.8mL at 74.4 degrees Celsius and 97.0 kpa. Calculate the molar mass of the gas.show all work

Answer 1

Following up on Jacques D answer, you would have the following:

n = moles of gas = PV/RT = (97 kPa )(0.9758 L)/(8.314 L-kPa/K-mol)(347.55K)

note that volume in is liters and temperature is in Kelvin. Answer will be in moles.

After finding n (moles), you simply divide 3.621 g by the number of moles to get g/mole = molar mass

Answer 2

In order to find molar mass (grams/mole) you need to find mass (given) and you need to find moles (use ideal gas law) , then divide as the units tell you to do to get grams per mole.

After rearrangement of IGL : moles are obtained from n = PV/(RT)

Usually, in chemistry, you use the gas constant R = .0821 liter•atm / mole•Kelvin

This means that you need to convert all your data to the appropriate units before plugging in.

If you want to use the official metric system R = 8.314 Pa•cubic meter/mole•Kelvin equal to 8.314 kPa•liter/mole•Kelvin, it's a little less work. You always have to use absolute temperature units, of course.

Good luck!