A 45.0 L steel tank at 20.0 °C contains acetylene gas, C₂H₂, at a pressure of 1.41 bar. Assuming ideal behaviour, how many grams of acetylene are in the tank?

Question

Quizplus · Accepted Answer

1. Convert the pressure to atm: 1.41 bar × 0.9869 atm/bar = 1.39 atm
2. Convert the temperature to Kelvin: 20.0°C + 273.15 = 293.15 K
3. Use the ideal gas law to calculate the number of moles of acetylene: 
n = PV/RT = (1.39 atm × 45.0 L) / (0.08206 L·atm/mol·K × 293.15 K) = 1.90 mol
4. Calculate the mass of acetylene using its molar mass: 
mass = n × M = 1.90 mol × 26.04 g/mol = 49.6 g
Therefore, the answer is C) 67.8 g (rounded to two significant figures).

A 450 L Steel Tank at 20