A 0.234-g sample of a gas in a 275-mL container at 23.5°C exerts a pressure of 0.292 atm What is the molar mass of the gas?

Question

Quizplus · Accepted Answer

The molar mass of the gas can be calculated using the ideal gas law equation, PV = nRT, where 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, convert the temperature to Kelvin (T = 23.5 + 273.15 = 296.65 K) and the volume to liters (V = 275 mL = 0.275 L). Rearrange the ideal gas law to solve for n (n = PV/RT). Then, calculate the molar mass by dividing the mass of the gas by the number of moles. Given: P = 0.292 atm, V = 0.275 L, T = 296.65 K, mass = 0.234 g, R = 0.0821 L·atm/(mol·K). Calculating n = (0.292 atm * 0.275 L) / (0.0821 L·atm/(mol·K) * 296.65 K) gives the number of moles. Then, molar mass = mass / n. The correct calculation leads to a molar mass close to 70.9 g/mol.

A 0234-G Sample of a Gas in a 275-ML Container at at 23.5°C