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.
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728 questions · page 22 of 37
- A. Heat of combustion
- B. Heat of neutralization
- C. Heat of decomposition
- D. Heat of formation
Explanation: This reaction involves the neutralization of an acid and a base.
Correct answer: Heat of neutralization- A. Temperature, Pressure, Work
- B. Enthalpy, Work, Pressure
- C. Enthalpy, Entropy, Internal Energy
- D. Heat, Enthalpy, Volume
Explanation: Enthalpy, Entropy, Internal Energy) - Correct: All three are state functions as they depend only on the state of the system
Correct answer: Enthalpy, Entropy, Internal Energy- A. Translational motion
- B. Vibrational motion
- C. Vibrational and rotational motion
- D. Translational and vibrational motion
Explanation: Vibrational and rotational motion) - Correct: Hydrogen molecules exhibit both vibrational and rotational motion along with translational…
Correct answer: Vibrational and rotational motion- A. Spontaneous reaction
- B. Non-Spontaneous reaction
- C. First law of thermodynamics
- D. All of the above options are correct
Explanation: Spontaneous heat transfer from hot to cold is also known as the second law of thermodynamics.
Correct answer: Spontaneous reaction- A. Endothermic reaction
- B. Exothermic reaction
- C. Thermochemistry
- D. Heat of formation
Explanation: Thermochemistry is the branch of chemistry concerned with the quantities of heat evolved or absorbed during chemical reactions.Endothermic…
Correct answer: Thermochemistry- A. Ionization energy
- B. Electronegativity
- C. Electron affinity
- D. Entropy
- E. Free energy
Explanation: As it can be seen in the equation, electrons are gained by the element chlorine to form a negative ion (anion).
Correct answer: Electron affinity- A. 394 kJ / mol
- B. -394 kJ / mol
- C. 197 kJ / mol
- D. -197 kJ / mol
Explanation: Formation of Carbon dioxide from Carbon and Oxygen is an exothermic reaction.
Correct answer: -394 kJ / mol- A. 43 K.J/Mole
- B. 37 K.J/Mole
- C. 25 KJ/Mole
- D. 19 K.J/Mole
Explanation: Since the initial internal energy of reactants in already 12KJ/mol.Threshold energy for reaction to proceed is 37kJ/mol.That means the…
Correct answer: 25 KJ/Mole- A. Hydrazine
- B. Both have equal enthalpy of formation
- C. Hydrogen gas
- D. Cannot be compared
Explanation: The performance of rocket fuel is measured by its enthalpy of combustion, which is the amount of heat released when one mole of the fuel…
Correct answer: Hydrogen gas- A. Taken in
- B. Give out to surroundings
- C. Neither given nor lost
- D. None of these
Explanation: An exothermic reaction is a chemical or physical reaction that releases heat. It gives out energy to its surroundings.
Correct answer: Give out to surroundings- A. Enthalpy
- B. Entropy
- C. Gibb's free energy
- D. None of these options are correct
Explanation: In an exothermic reversible reaction, the change in Gibbs free energy (ΔG) can have a positive value at lower temperatures due to the…
Correct answer: Gibb's free energy- A. Charge to size ratio
- B. Polarizability of anions
- C. Polarization power of Cations
- D. All of these
Explanation: Hydration energy is the amount of energy released or absorbed when ions in gaseous state are surrounded by water molecules to form…
Correct answer: All of these- A. Energy content of product is more
- B. Energy content of reactant is less
- C. Heat is transferred from the system to the surrounding
- D. Heat is transferred from the surrounding to the system
Explanation: An exothermic reaction is a chemical reaction that releases energy in the form of heat.
Correct answer: Heat is transferred from the system to the surrounding- A. Route reaction takes completion
- B. Temperature of reactants
- C. Concentration of products
- D. Concentration of reactants
Explanation: Option A is correct since it states the correct definition of Hess's law which is: If a chemical change takes place by several different…
Correct answer: Route reaction takes completion- A. Boiling point.
- B. Chemical bonding.
- C. Quantum study.
- D. Physical properties.
Explanation: Thermodynamics explain chemical bonding. chemical bonding, any of the interactions that account for the association of atoms into…
Correct answer: Chemical bonding.- A. Enthalpy of formation
- B. Enthalpy of combustion
- C. Enthalpy of neutralization
- D. Enthalpy of sublimation
Explanation: The standard enthalpy of formation of a compound is the amount of heat absorbed or evolved (enthalpy change) when one mole of a compound…
Correct answer: Enthalpy of formation- A. Gases
- B. Liquids
- C. Liquids and solids
- D. Liquids and Gases
Explanation: In the case of liquids and solids, the changes in the state do not cause significant volume change i.e. ΔV=0.
Correct answer: Liquids and solids- A. Dissolution
- B. Crystallization
- C. Bond breaking
- D. Condensation
Explanation: The process of dissolving can be endothermic (temperature goes down) or exothermic (temperature goes up).
Correct answer: Dissolution- A. 82.5 Cal
- B. 80 Cal
- C. 85.2 Cal
- D. 58.8 Cal
Explanation: Option C is correct as Cp and CV for a diatomic gas are 7/2 R and 5/2 R respectively.
Correct answer: 85.2 Cal- A. 524.1
- B. 41.2
- C. −262.5
- D. −41.2
Explanation: Option B is correct according to the following solution:
Correct answer: 41.2