Question

Calculate the number of moleacules in 22.4L of CH4 gas at STP.

Answer 1

At STP of 273.15 K (0°C) and 1 atm, the molar volume of a gas is 22.4 L/mol.

So at STP, if you have 22.4 L of CH4, you have one mole of CH4.

1 mole of molecules = 6.02×10^23 molecules

Mathematical proof through dimensional analysis:

22.4L CH4 × 1mol CH4/22.4L CH4 × 6.02×10^23 CH4 molecules/mol CH4 = 6.02×10^23 CH4 molecules