Question

Calculate the number of moles of hydrogen gas present in a 0.5 dm³ sample of hydrogen gas at a pressure of 101.325 kPa at 27 °C.

Answer 1

Given: V = 0.5 dm³ = 0.5 × 10^-3 m³, P = 101.325 kPa = 101.325 × 10³ Pa = 101.325 × 10³ Nm^-2
T = 27 °C = 27 + 273.15 K = 300.15 K, R = 8.314 J K^-1 mol^-1
To find: n = number of moles of gas
Formula: PV = nRT
Calculation: According to ideal gas equation,
\(n=\frac{PV}{RT}=\frac{101.325\times10^3\times0.5\times10^{-3}}{8.314\times300.15}=0.020 mol\)
Ans: The number of moles of hydrogen gas present in the given volume is 0.020 moles.