A sample of gas weighs 0.250 g and occupies a volume of 112 cm3 at 0 °C and 1 atm. The molecular weight of this gas is ________.

Question

Quizplus · Accepted Answer

First, we need to convert the volume to liters and the mass to kilograms:
- 112 cm³ = 0.112 L
- 0.250 g = 0.00025 kg

Next, we can use the ideal gas law to find the number of moles of gas present:
PV = nRT
where P = 1 atm, V = 0.112 L, T = 273 K (0 °C + 273), and R = 0.0821 L·atm/mol·K.

n = (PV)/(RT) = (1 atm × 0.112 L)/(0.0821 L·atm/mol·K × 273 K) ≈ 0.004

Finally, we can use the definition of molecular weight to find the answer:
molecular weight = mass/number of moles
= (0.00025 kg)/(0.004 mol)
= 62.5 g/mol

Choice B is the closest answer to this value.

A Sample of Gas Weighs 0