How many liters are in 223.5G of C2H6 gas?

Question

How many liters are in 223.5G of C2H6 gas?

A.7.4L

B.116.4L

C. 9.9L

D. 15.4L

Answer 1

Hello, Elizabeth,

We'll assume the gas is at standard temperature and pressure (STP).

One mole of any gas occupies 22.4 liters at STP. We need the number of moles of C₂H₆ (ethane) gas, so determine it's molar mass: Add the atomic masses of the individual elements:

2C = 2*12.01=24.02 amu

6H = 6*1.008 = 6.048 amu

Total C₂H₆ = 30.07 amu

We can use the same number to tell us how many grams are in one mole of ethane. Just change amu into g/mole, and we now know it takes 30.07 grams of ethane to make 1 mole of ethane, or 30.07g/mole.

We have 223.5 grams of ethane gas. To find the number of moles that represents, divide by the molar mass:

(223.5g ethane)/(30.07 g/mole) = 7.433 moles C₂H₆

The grams cancel and moles moves to the top. We have 7.433 moles of ethane.

Since "1 mole of any gas at standard temperature and pressure ( STP at 273 K and 1 atm.) occupies a volume of 22.4 L." , this becomes a simple conversion:

At STP: (7.433 moles ethane)*(22.4 L/mole) = 166.5 liters. To put this into perspective, a human adult lung moves around 1 liter of air for every breath cycle. Put the matches away.

I hope this helps,

Bob

A