How many times is pentane (C5H12) heavier than methane?

Pentane – C5H12.
Methane – CH4.
1) Molar mass of pentane: 12 * 5 + 1 * 12 = 60 + 12 = 72.
2) Molar mass of methane: 12 + 1 * 4 = 16.
Let’s take the amount of substances equal to one mole.
Then, we find the masses of both substances by multiplying their molar mass by their amount of substances:
3) Mass of pentane: 72 * 1 = 72g.
4) Mass of methane: 16 * 1 = 16g.
Then, the mass difference is equal to: 72/16 = 4.5 times.
Answer: pentane is 4.5 times heavier than methane.