Answer: 32 grams of O2.
Explanation:
First, find the molar mass of methane
C = (1 * 12) = 12
H = (4 * 1) = 4
Molar mass is 16 g/mole
So, 8 grams of methane is 1/2 a mole
Since the ratio of methane to oxygen is 1:2, you need twice as many moles of O2, in this case, that's 1 mole of O2.
Find out how many grams is 1 mole of O2
The molar mass of O2 is
O2 = 2*16 = 32 grams per mole
