MDCAT Chemistry — Thermochemistry
Thermochemistry is a core Chemistry topic in the PMDC MDCAT syllabus, covering 5 subtopics. Below are the subtopics to revise, how often the topic appears in past papers, and real past-paper MCQs to try.
Subtopics (5)
- Enthalpy of Reaction
- Exothermic and Endothermic Reactions
- First Law of Thermodynamics
- Hess's Law
- System, Surroundings, State Functions
How Thermochemistry is tested
Across the 16 MDCAT past papers on ParhaiKrlo, Thermochemistry accounts for 46 questions. It appears in all 16, about 2.9 questions a paper. The heaviest was MDCAT 2019, with 5 questions, and the most recent is MDCAT 2025, with 2.
| Paper | Questions |
|---|---|
| MDCAT 2025 | 2 |
| MDCAT 2024 | 3 |
| MDCAT 2023 | 3 |
| MDCAT 2022 | 4 |
| MDCAT 2019 | 5 |
| MDCAT 2018 | 2 |
| MDCAT 2017 | 2 |
| MDCAT 2016 | 5 |
| MDCAT 2015 | 5 |
| MDCAT 2014 | 4 |
| MDCAT 2013 | 2 |
| MDCAT 2012 | 1 |
| MDCAT 2011 | 1 |
| MDCAT 2010 | 3 |
| MDCAT 2009 | 2 |
| MDCAT 2008 | 2 |
Thermochemistry MCQs from the MDCAT past papers
Try each one before opening the answer. Each comes with a short explanation.
- Q1 · MDCAT 2025 · Thermochemistry
The majority of reactions taking place at ordinary temperatures (with ΔH) are:
- A.Endothermic
- B.Exothermic
- C.Thermally unstable
- D.Reversible
Show answer
Answer: B. Exothermic — Most reactions at ordinary temperatures are exothermic.
- Q2 · MDCAT 2024 · Thermochemistry
Which of the following is CORRECT Arrhenius equation?
- A.K = Ae^(−Ea/QT)
- B.K = Ae^(−Ea/RT)
- C.K = Ae^(−Ea/ST)
- D.K = Ae^(−Ea/UT)
Show answer
Answer: B. K = Ae^(−Ea/RT) — The Arrhenius equation is K = Ae^(-Ea/RT).
- Q3 · MDCAT 2023 · Thermochemistry
The process of heat flow between hotter and colder gases remains continued until all the molecules have equal:
- A.Average translational kinetic energy
- B.Average rotational kinetic energy
- C.Average translational potential energy
- D.Average vibrational kinetic energy
Show answer
Answer: A. Average translational kinetic energy — Heat flow between gases continues until their molecules reach equal average translational kinetic energy — that is, thermal equilibrium.