Question

A 3.28 g sample of gas occupies 1.25 L at standard temperature pressure (STP; 0 °C and 1 atm) conditions. What is its molar mass?**

a) 0.18 g/mol
b) 2.50 g/mol
c) 8.21 g/mol
d) 22.41 g/mol

Answer 1

To calculate the molar mass of a gas at STP, divide the mass of the sample by the volume of the sample and multiply by the molar volume at STP.

Step-by-step explanation:

Molar Mass Calculation

To calculate the molar mass of a gas, we need to use the ideal gas law and the molar volume at STP (standard temperature and pressure). To find the molar mass, we can use the following equation:

Molar Mass = (Mass of Sample / Volume of Sample) x Molar Volume at STP

Given that the mass of the sample is 3.28 g and the volume of the sample is 1.25 L, we can substitute these values into the equation:

Molar Mass = (3.28 g / 1.25 L) x 22.4 L/mol

Molar Mass = 17.228 g/mol

Therefore, the molar mass of the gas is approximately 17.228 g/mol.