If 50.75 g of a gas occupies 10.0 L at STP, 129.3 g of the gas will occupy L at STP.
A) 50.8
B) 25.5
C) 5.08
D) 12.9
E) 3.92

Question

Quizplus · Accepted Answer

According to the Avogadro's Law, equal volumes of gases at the same temperature and pressure contain equal numbers of particles. Therefore, we can use the following equation:

n1/V1 = n2/V2

where n is the number of moles and V is the volume.

At STP, the molar volume of a gas is 22.4 L/mol. Therefore, we can calculate the number of moles of the gas present in the first case:

n1 = 50.75 g / (molar mass of the gas) 
n1 = 50.75 g / (molar mass of the gas) x (1 mol / 22.4 L) 
n1 = 2.27 mol

Now, we can use this value to calculate the volume occupied by the second amount of gas:

n2 = 129.3 g / (molar mass of the gas) 
n2 = 129.3 g / (molar mass of the gas) x (1 mol / 2.27 mol) 
n2 = 56.9 mol

V2 = n2 x 22.4 L/mol 
V2 = 56.9 mol x 22.4 L/mol 
V2 = 1274.56 L

Rounding this value to the nearest tenth gives us 1274.6 L, which is closest to choice B: 25.5 L.

If 5075 G of a Gas Occupies 10