A sample of gas weighs 0.250 g and occupies a volume of 112 cm³ at 0 °C and 1 atm.The molar mass of the gas is ________. A)25.0 g/mol B)50.0 g/mol C)2.23 g/mol D)8.0 g/mol E)200 g/mol

Question

Quizplus · Accepted Answer

We can use the ideal gas law to find the number of moles of gas present in the given sample:

PV = nRT

where P = 1 atm, V = 112 cm3 = 0.112 L, T = 273 K (0 °C + 273), and R is the gas constant. Solving for n, we get:

n = PV/RT = (1 atm)(0.112 L)/(0.0821 L⋅atm/mol⋅K)(273 K) = 0.00419 mol

Next, we can use the definition of molar mass (mass/moles) to find the molar mass of the gas:

molar mass = mass/number of moles = 0.250 g/0.00419 mol ≈ 59.67 g/mol

Of the given choices, B is the closest to this value, so the answer is (B) 50.0 g/mol.

A Sample of Gas Weighs 0