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 17 of 37
321. The property of the system which does not depend upon the path followed by the system is called as?
- A. State function
- B. Path function
- C. Dependent function
- D. Independent function
Explanation: A state function is a macroscopic property of a system which has some definite values for initial and final states, and which is…
Correct answer: State function- A. -110 kJ/mol
- B. -210 kJ/mol
- C. -111 kJ/mol
- D. None of these options is correct
Explanation: By constructing a Hess' Cycle for CO along with the relevant data given relating to the standard enthalpy change of formation of CO2 and…
Correct answer: -110 kJ/mol- A. ΔE = ΔH
- B. ΔE = q + p
- C. ΔE = q+w
- D. ΔE = -PΔV
Explanation: The first law of thermodynamics is given as ΔE=q+w, where ΔE is the change in internal energy of a system, q is the net heat transfer (the…
Correct answer: ΔE = q+w- A. 200 atm
- B. 25 atm
- C. 20 atm
- D. 75 atm
Explanation: High-Pressure oxygen is required to ensure the sample burns completely in the bomb vessel.
Correct answer: 20 atm325. The only thing which can predict that if the reaction will be spontaneous or nonspontaneous is:
- A. Enthalpy change
- B. Free energy of the system
- C. Energy Change
- D. Temperature Change
Explanation: Free energy of the system also known as the Gibbs free energy determines if the reaction is spontaneous or not.
Correct answer: Free energy of the system- A. Vibrational
- B. Translational
- C. Rotational
- D. Static
Explanation: Kinetic energy needs an object to be in motion.
Correct answer: Static- A. Highly exothermic
- B. Slightly endothermic
- C. Zero
- D. Slightly exothermic
Explanation: The heat of solution for NaCl is slightly endothermic which allows for its dissolution spontaneousy in water since the increase in entropy…
Correct answer: Slightly endothermic- A. Exothermic reaction
- B. Endothermic reaction
- C. Spontaneous reaction
- D. Nonspontaneous reaction
Explanation: In a combustion reaction, heat is always given off as the compound burns in excess oxygen to given carbon dioxide.
Correct answer: Exothermic reaction- A. Initial condition of the system
- B. Final condition of the system
- C. Path of the system
- D. Both initial and final conditions of the system
Explanation: STATE FUNCTION:A state function is the property of the system that depends on the initial and final states and is independent of the path…
Correct answer: Both initial and final conditions of the system- A. Addition Reaction
- B. Substitution Reaction
- C. Neutralization Reaction
- D. Reversible Reaction
Explanation: OPTION A: Addition reaction occurs when two or more reactants combine to form a product without the loss of any atoms present in the…
Correct answer: Neutralization Reaction- A. Reversible Reaction
- B. Spontaneous Reaction
- C. Endothermic Reaction
- D. All of these options are correct
Explanation: OPTION A: The reactions that do not go to completion and the products formed react to re-form the reactants are called reversible…
Correct answer: Spontaneous Reaction- A. W = P V
- B. W = ΔP V
- C. W = P ΔV
- D. W = P + ΔV
Explanation: W = P ΔVThis is called pressure-volume work and is positive when it is done on the system.
Correct answer: W = P ΔV- A. Microscopic
- B. Dependent
- C. Macroscopic
- D. Constant
Explanation: A state function is a macroscopic property of a system which has some definite values for initial and final states, which is independent…
Correct answer: Macroscopic- A. Constant
- B. Variable
- C. Depends on the strength of acid
- D. Depends on the strength of base
Explanation: The enthalpy of neutralization of all strong acids and strong bases is always constant i.e. -57.1 kJ.
Correct answer: Constant- A. System
- B. Surroundings
- C. Boundary
- D. None of These
Explanation: The correct answer is Boundary. In thermochemistry, the piston in the cylinder serves as a boundary that separates the system from its…
Correct answer: Boundary- A. Evaporation
- B. Fusion
- C. Sublimation
- D. Respiration
Explanation: Exothermic processes generate heat, which raises the heat from the surrounding environment.
Correct answer: Respiration- A. Electrochemistry
- B. Biochemistry
- C. Thermochemistry
- D. Analytical Chemistry
Explanation: Thermochemistry is the study of the heat energy which is associated with chemical reactions and/or phase changes such as melting and…
Correct answer: Thermochemistry- A. Endothermic reactions
- B. Exothermic reactions
- C. Exergonic reactions
- D. Heat releasing reactions
Explanation: Endothermic reactions are those reactions which requires heat or energy from surrounding.When an endothermic reaction occurs, the heat…
Correct answer: Endothermic reactions- A. Temperature (T)
- B. Volume (V)
- C. Enthalpy (E)
- D. Heat (q)
Explanation: Heat is NOT a state function. Heat is the transfer of energy between a system and its surroundings due to a temperature difference.
Correct answer: Heat (q)- A. Heat
- B. Energy
- C. Work
- D. All of these
Explanation: Heat is measured in joules. The energy units in which heat changes, usually expressed in SI system are joule (J) and kilojoule (kJ).
Correct answer: All of these