Ideal gas law: A 25-L container holds ideal hydrogen (H₂) gas at a gauge pressure of 0.25 atm and a temperature of 0°C. What mass of hydrogen gas is in this container? The ATOMIC mass of hydrogen is 1.0 g/mol, the ideal gas constant is R = 8.314 J/mol ∙ K = 0.0821 L ∙ atm/mol ∙ K, and 1.00 atm = 101 kPa. A) 1.4 g B) 2.8 g C) 4.2 g D) 5.6 g E) 6.3 g

Question

Quizplus · Accepted Answer

First, convert the temperature to Kelvin: 0°C + 273.15 = 273.15 K. The gauge pressure is 0.25 atm, but the total pressure must include atmospheric pressure (1 atm), so the total pressure is 1.25 atm. Use the ideal gas law: PV = nRT. Solve for n (moles of gas): n = PV / RT = (1.25 atm)(25 L) / (0.0821 L∙atm/mol∙K)(273.15 K) ≈ 1.4 moles. The molar mass of hydrogen gas (H2) is 2.0 g/mol (since each molecule has 2 atoms), so the mass is 1.4 moles * 2.0 g/mol = 2.8 g.

Ideal Gas Law: a 25-L Container Holds Ideal Hydrogen (H2)

Ideal Gas Law: a 25-L Container Holds Ideal Hydrogen (H₂)