Chemistry Help!?

Question

What is the volume at STP of 2.66 moles of Methane (CH4) How do you do this?? please help!

Answer 1

1 mole of any ideal gas (which we will assume methane to be an ideal gas) occupies a volume of 22.4 Liters at STP.

Since the question specifies STP, it is safe for us to assume that we are suppose to treat methane as an ideal gas and not look up its density somewhere (even though that is a perfectly valid way). It will come in extremely useful if you just memorize this value of 22.4 Liters per mole of an ideal gas at STP, you can use this conversion factor a lot, it is very helpful. But if you cannot memorize it, you can always derive it from the ideal gas law,
PV = nRT
P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature (in Kelvin).
At STP, P = 1 atm, R = about .0821 J / mole K, and T = 273.15 K.

Volume of methane = moles of methane * 22.4 Liters per mole
Volume of methane = (2.66 moles) * (22.4 L / mol)
Volume = 59.6 Liters

Answer 2

Methane has a density of 0.717 kg/m^3.

A mole of methane has a mass of 16g so 2.66 moles has a mass of 42.6g.

V = m/d = 0.0426 kg / 0.717 kg/m^3 = 0.0593 m^3 = 59.3 liters

Answer 3

Just use PV=nRT
substitute standart values for R-.0821, for T-273 and P standard is 760