Question

An experiment shows that a 116 mL gas sample has a mass of 0.171 g at a pressure of 721 Torr and a temperature of 30 ∘C. What is the molar mass of the gas?

A. 2.01 g/mol
B. 4.02 g/mol
C. 32.00 g/mol
D. 64.00 g/mol

Answer 1

To find the molar mass of the gas, we need to use the ideal gas law equation, which is PV = nRT. By rearranging the equation and plugging in the given values, we can calculate the number of moles of the gas and then calculate the molar mass.

Step-by-step explanation:

To find the molar mass of the gas, we need to use the ideal gas law equation, which is PV = nRT. Here, P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature in Kelvin.

First, we need to convert the given values to the correct units. The volume of the gas is given as 116 mL, which needs to be converted to liters by dividing by 1000. The pressure is given as 721 Torr, and the temperature is given as 30 °C, which needs to be converted to Kelvin by adding 273.15.

Using the equation, we can solve for n, the number of moles. Rearranging the equation to solve for n, we have n = PV / RT. Plugging in the values and the value of the ideal gas constant, we can calculate the number of moles of the gas. Finally, we can calculate the molar mass by dividing the mass of the gas (given as 0.171 g) by the number of moles.