1) for this, you have to first find the volume of 1 mole of methane by adding the molar mass of each of the elements in the formula (H=1 C=12.01) so CH4 = 12.01+4, so 1 mole or 6.02x10^23 particles of CH4 weighs 16.01 grams. after that, im not so sure. but i hoped that helped.