Assess students' ability to apply the ideal gas law (PV = nRT) to calculate pressure, volume, temperature, or amount of gas (moles) across a range of problems. Expect rearrangement of the formula, correct selection and use of R with consistent units, temperature and pressure unit conversions (K, atm, Pa), and multi-step problems that may involve molar mass or mixtures; solutions should show algebraic work and unit analysis.