All question types · Thermodynamics

Moles of an ideal gas

A-Level (AQA) · C3L6 · UKChO Round 1 · IChO · unreviewed

n = pV/RT in SI units: Pa × m³ (or kPa × dm³, which also gives J) and T in kelvin.

Practise this with fresh numbers

Worked example

How many moles of an ideal gas occupy 18900 cm³ at 3.56 atm and 64 °C?

1. Ideal gas equation: solve for n
$n = \dfrac{pV}{RT}$
= 2.432 mol

Answer: n = 2.43 mol

Method

n = pV/RT in SI units: Pa × m³ (or kPa × dm³, which also gives J) and T in kelvin.

Formulas used

Ideal gas equation
$pV = nRT$

Practise this with fresh numbers