Terms Used in Thermochemistry

Terms Used in Thermochemistry MDCAT MCQs with answers

10 past paper MCQs on Terms Used in Thermochemistry, from the Thermochemistry and Energetics of Chemical Reactions unit of MDCAT Chemistry. The year each question appeared is shown where known; tap “Show answer” for the correct option and a short solution.

Read the notes first Practise the unit as a quiz

1.Which of the following terms is a state function? (MDCAT 2022)

  1. freezing
  2. decomposition
  3. sublimation
  4. enthalpy
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Correct answer: (d) enthalpy

Enthalpy depends only on the state of the system, not on the path by which it got there.

2.Which of the following is NOT a state function? (SIBA MDCAT 2025)

  1. Enthalpy
  2. Work
  3. Internal energy
  4. Pressure
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Correct answer: (b) Work

Work depends on the path taken, so it is not fixed by the state of the system.

3.Q.89 Which of the following term is state function? (UHS MDCAT 2023)

  1. freezing
  2. decomposition
  3. sublimation
  4. enthalpy
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Correct answer: (d) enthalpy

Enthalpy depends only on the state of the system, not on how it got there.

4.One calorie is equal to: (SZABMU MDCAT 2023)

  1. 4.18 KJ
  2. 4.18 J
  3. 0.418 KJ mole-1
  4. 0.418 KJ
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Correct answer: (b) 4.18 J

One calorie is $4.18\,\mathrm{J}$.

5.What is the reason of energy changes in chemical reactions? (UHS MDCAT 2023)

  1. Bond formation
  2. Bond breakage
  3. Bond formation and breakage
  4. Ionic bonds
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Correct answer: (c) Bond formation and breakage

Breaking bonds absorbs energy and forming them releases it; the difference is the heat of reaction.

6.What is the unit of heat capacity? (UHS MDCAT 2023)

  1. JK-1
  2. kJmol-1
  3. kJ/K
  4. kJ.mol
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Correct answer: (a) JK-1

Heat capacity is heat per unit rise in temperature, so its unit is the joule per kelvin.

7.One Calorie is equivalent to: (NUMS MDCAT 2022)

  1. 4.184 J
  2. 4.184 kJ
  3. 0.4184 J
  4. 0.4184 kJ
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Correct answer: (a) 4.184 J

One calorie is $4.184\,\mathrm{J}$.

8.If water is present in a cup placed on a table, what will be the system in this case? (PMC Practice 2021)

  1. Water
  2. Water in the cup
  3. Whole table
  4. All of these options are correct
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Correct answer: (a) Water

The system is the part under study, here the water; the cup and the table are its surroundings.

9.Enthalpy is measured at _____: (UHS MDCAT 2017)

  1. 300 K and 2 atm
  2. 300 K and 1atm
  3. 298 K and 1 atm
  4. 295 K and 1 atm
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Correct answer: (c) 298 K and 1 atm

Standard enthalpies are quoted at $298\,\mathrm{K}$ and one atmosphere.

10.Determine the value of Enthalpy of formation of NH4Cl (UHS MDCAT 2017)

  1. – 788 kJmol-1
  2. -314.55 kJmol-1
  3. -692 kJmol-1
  4. None of the given options
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Correct answer: (b) -314.55 kJmol-1

The formation of ammonium chloride from its elements releases about $315\,\mathrm{kJ\,mol^{-1}}$.

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