5 past paper MCQs on Charles's Law, from the Gases unit of MDCAT Chemistry. The year each question appeared is shown where known; tap “Show answer” for the correct option and a short solution.
1.At constant pressure, at which temperature will the volume of a gas become twice its volume at $0^\circ$C? (MDCAT 2020)
Correct answer: (c) $273^\circ$C
Volume goes as the absolute temperature, so it doubles when 273 K becomes 546 K, which is $273^\circ$C.
2.A gas has volume 10dm3 at 10°C. At what temperature is volume reduced to half? (NUMS MDCAT 2024)
Correct answer: (c) 142K
At constant pressure the volume follows the absolute temperature, so halving it halves $283\,\mathrm{K}$ to about $142\,\mathrm{K}$.
3.According to Charles law volume of gas reduces to zero at: (SZABMU MDCAT 2023)
Correct answer: (c) -273.15 O C
Extrapolating the volume line to zero gives $-273.15^{\circ}\mathrm{C}$.
4.The quantitative relationship between absolute temperature (T) and volume (V) of a fixed amount of a gas at constant pressure (P) can be best described by: (PMC MDCAT 2022)
Correct answer: (c) V/T =K
At constant pressure the volume is proportional to the absolute temperature, so $V/T$ is constant.
5.Liquid in the container has a temperature 70°C. What will be the temperature on the Kelvin scale? (UHS MDCAT 2018)
Correct answer: (b) 343 K
$70+273$ is $343\,\mathrm{K}$.