Free Thermochemistry and Energetics of Chemical Reactions MCQs with Answers
728 Thermochemistry and Energetics of Chemical Reactions MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Thermochemistry measures energy changes in chemical reactions and distinguishes exothermic from endothermic processes. Work covers systems, surroundings and state functions, internal energy, the first law of thermodynamics, enthalpy and Hess's law, including the sign conventions used when heat enters or leaves a system.
Last updated
728 questions · page 24 of 37
- A. Atomization
- B. Combustion
- C. Neutralization
- D. Solution
Explanation: A is correct. Atomization involves bond breaking and bond breaking is endothermic.
Correct answer: Atomization- A. It is an endothermic process
- B. It can be represented as H3O+(aq)+ OH.(aq) → 2H2O(I)
- C. The enthalpy change per mole of H2O formed is independent of the acid or alkali used as they are strong
- D. Both B and C
Explanation: C is true. Standard enthalpy change of neutralization is approximately the same for every strong base and strong acid i.e. -57.4 kJmol-1
Correct answer: The enthalpy change per mole of H2O formed is independent of the acid or alkali used as they are strong- A. A
- B. B
- C. C
- D. D
Explanation: B is correct. The energy of products should be greater than that of reactants in an endothermic reaction.
Correct answer: B464. Lattice energy (∆H∘latt) helps to explain all of the following properties of ionic compounds EXCEPT:
- A. Structure
- B. Heat of solution
- C. Bonding
- D. Dipole Moment
Explanation: Lattice energy can not explain the dipole moment of ionic compounds. Ionic compounds are held tight in a giant lattice, so the…
Correct answer: Dipole Moment- A. The study of heat changes accompanying a chemical reaction is known as thermochemistry
- B. Thermodynamics is a branch of physics that deals with heat, work and temperature
- C. Both A and B
- D. Neither A nor B
Explanation: Option C is correct because both statements A and B are accurate descriptions of thermochemistry and thermodynamics.
Correct answer: Both A and B- A. CCI4
- B. Al2O3
- C. B2O3
- D. MgO
Explanation: Option D, MgO (magnesium oxide), is correct because its standard enthalpy change (∆H∘) can be measured directly by a…
Correct answer: MgO- A. ∆Hv
- B. ∆H°sol
- C. ∆H°BDE
- D. ∆Hi
Explanation: Option B, ∆H°sol, refers to the standard enthalpy change of solution, which is the enthalpy change when one mole of a substance dissolves…
Correct answer: ∆H°sol- A. ∆H°n
- B. ∆H°at
- C. ∆H°sol
- D. ∆H°f
Explanation: Option A, "∆H°n," is correct because a glass calorimeter is typically used to measure the heat of a chemical reaction at constant…
Correct answer: ∆H°n- A. Remains constant
- B. Decreases
- C. Increases
- D. Remains unchanged
Explanation: Option b is correct because in an endothermic reaction, heat is absorbed from the surroundings, causing a decrease in temperature.
Correct answer: Decreases- A. A
- B. B
- C. C
- D. D
Explanation: Option d is correct because it makes an inaccurate generalization about the relative magnitudes of qv and qp without specifying the…
Correct answer: D- A. A
- B. B
- C. C
- D. D
Explanation: The term system is used for anything (materials) under test in the laboratory, or under consideration in the classroom for the purpose of…
Correct answer: B- A. Temperature
- B. Physical state of reactants and products
- C. Reaction conditions
- D. All of these
Explanation: The temperature at which a reaction occurs significantly affects the heat of reaction.
Correct answer: All of these- A. Chemical nature of a substance
- B. Temperature
- C. Pressure and volume
- D. Path
Explanation: In thermodynamics, the internal energy of a system is a state function, which means it depends only on the initial and final states of the…
Correct answer: Path- A. ∆H°f > ∆Hhyd
- B. ∆Hhyd > ∆H°f
- C. ∆Hhyd = ∆H°f
- D. ∆Hhyd ≤ ∆H°f
Explanation: For an ionic solid to dissolve in water, it must overcome the energy barrier associated with breaking the ionic bonds in the solid and the…
Correct answer: ∆Hhyd > ∆H°f- A. To study processes at constant volume (∆V = 0) only
- B. To study processes at constant pressure (∆P = 0) only
- C. Both A and B
- D. Neither A nor B
Explanation: To study processes at constant volume (∆V = 0): The first law of thermodynamics is applicable to processes that occur at constant volume.
Correct answer: Both A and B- A. Law of mass action
- B. Hess's Law
- C. Joule's Law
- D. First law of thermodynamics
Explanation: This statement is related to Hess's law which states that: "If a chemical change takes place by several different routes, the overall…
Correct answer: Hess's Law- A. ∆Hlatt = ∆Hf - ∆Hx
- B. ∆Hlatt = ∆Hx - ∆Hf
- C. ∆Hlatt = ∆Hx + ∆Hf
- D. ∆Hlatt = ∆Ha - ∆Hx
Explanation: The lattice energy, gives us some idea of the force of attraction between Na+ and Cl- ions in crystalline sodium chloride.
Correct answer: ∆Hlatt = ∆Hf - ∆Hx- A. State
- B. State function
- C. Surrounding
- D. System
Explanation: The macroscopic property of a system that has definite values for the initial and final states and is independent of the path taken to…
Correct answer: State function- A. ∆H
- B. ∆E
- C. ∆T
- D. ∆G
Explanation: Based on the information provided, the correct option for predicting whether the reaction is spontaneous or non-spontaneous is ∆G.
Correct answer: ∆G- A. 270K
- B. 200K
- C. 298K
- D. 273K
Explanation: The correct option for the temperature at which the standard enthalpy change is measured is C) 298K (Kelvin).
Correct answer: 298K