
Jason T. answered 04/20/20
Experienced tutor and teacher in math, chemistry, and chem engineering
These are all small gas molecules at STP (standard temperature and pressure), so we will assume ideal gas law (carbon dioxide is polar so would have the largest deviation from ideal gas behavior).
1 mol of ideal gas occupies 22.4 L at STP.
75.0 L CH4 * (1 mol / 22.4 L) = 3.348 mol CH4
molar mass of CH4 = 16.04 g / mol
3.348 mol CH4 * (16.04 g / mol) = 53.7 g CH4
We use 3 significant figures in the answer because 3 were given in the problem statement, "75.0"
Keep using 22.4 L / mol and each compounds molar mass to solve the rest of the problems. Also remember Avogadro's number, that there are 6.022*10^23 molecules per mole for the last 2 problems. If you need further assistance, please book a session with me!
Kit L.
thank you!04/20/20