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 18 of 37
- A. Born Haber cycle
- B. Joule's principle
- C. Hess's law
- D. Law of conservation of energy
Explanation: Hess's Law states that the overall enthalpy change of a reaction is independent of the pathway followed as long as the initial and final…
Correct answer: Hess's law- A. Enthalpy of formation
- B. Enthalpy of neutralization
- C. Enthalpy of Sublimation
- D. Enthalpy of reaction
Explanation: In the reaction above an acid base reaction is taking place which is also known as neutralisation with hydrogen ion from the acid reacting…
Correct answer: Enthalpy of neutralization- A. Entropy
- B. Enthalpy
- C. Internal energy
- D. Heat energy
Explanation: The total of all the possible kinds of energies in a system is called its internal energy including Kinetic energy and Potential energy.
Correct answer: Internal energy- A. Reaction conditions
- B. Concentration
- C. State of system
- D. All of these
Explanation: The state of a system is the condition of a system. SUPPOSE take a beaker.
Correct answer: State of system- A. Enthalpy change
- B. Surroundings
- C. Path of the reaction
- D. System
Explanation: State functions are independent of the path or process by which a system reaches a particular state.
Correct answer: Path of the reaction- A. Solid phase
- B. Gases phase
- C. Liquids, solids and solution
- D. None of these
Explanation: This is often the case for reactions that take place in open containers or in systems where the pressure remains relatively constant.
Correct answer: Liquids, solids and solution- A. Endothermic reactions
- B. Exothermic reactions
- C. Endergonic reactions
- D. Heat gaining reactions
Explanation: Option B "EXOTHERMIC REACTIONS" are those reactions in thermodynamics in which Heat is evolved or released (from system to surrounding)…
Correct answer: Exothermic reactions- A. Endothermic reaction
- B. Exothermic reaction
- C. Irreversible reaction
- D. Redox reaction
Explanation: An exothermic reaction is a chemical reaction that releases heat to its surroundings, resulting in an increase in temperature.
Correct answer: Exothermic reaction- A. Newtons
- B. Joule
- C. Newton/metre
- D. All of these
Explanation: The S.I unit of work is joule, work is also a form in which energy is transferred from one system to another.
Correct answer: Joule- A. 1st law
- B. 2nd law
- C. 3rd law
- D. None of these
Explanation: The statement reflects the 1st law of thermodynamics. The 1st law of thermodynamics, also known as the law of energy conservation, states…
Correct answer: 1st law- A. q=m s ∆T
- B. E=q m ∆T
- C. E=m s ∆T
- D. q=m e ∆T
Explanation: q = m * s * ∆T is correct It takes into account the mass of the solution, the specific heat capacity of the solution, and the change in…
Correct answer: q=m s ∆T- A. ∆H= qv+ w
- B. ∆E= (q)v
- C. ∆H=(q)v
- D. ∆E= (q)v + PV
Explanation: ΔE= q - ΔW ΔE = q - PΔV Where ΔE = change in internal energy q= heat ΔW = work done P = pressure ΔV = volume The equation becomes , q = ΔE…
Correct answer: ∆E= (q)v- A. Entropy
- B. Work function
- C. Total heat content
- D. Internal energy
Explanation: Enthalpy is the measurement of energy in a thermodynamic system. The quantity of enthalpy equals to the total content of heat of a system…
Correct answer: Total heat content- A. Second law of thermodynamics
- B. Third law of thermodynamics
- C. First law of thermodynamics
- D. Zeroth law of thermodynamics
Explanation: The correct answer is the First Law of Thermodynamics, which directly restates the Law of Conservation of Energy.
Correct answer: First law of thermodynamics- A. ∆G
- B. ∆H
- C. ∆E
- D. ∆H-∆E
Explanation: Delta G (ΔG) represents the change in Gibbs free energy of a chemical reaction or a physical process The heat absorbed by a substance at…
Correct answer: ∆H- 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 solids and liquids, the changes in the state do not cause significant volume change, i.e ΔV = 0.
Correct answer: Liquids and solids- A. 15 Kj/mol
- B. -17kJ/mol
- C. 16.2 kJ/mol
- D. -16.5 kJ/mol
Explanation: Remember that the enthalpy of solution of NH4Cl is +16.2 kJ/mol.
Correct answer: 16.2 kJ/mol- A. Endothermic reaction
- B. Exothermic reaction
- C. Spontaneous reaction
- D. Chemical reaction
Explanation: Evaporation of water is an endothermic reaction. During evaporation, water molecules absorb heat from the surroundings and change into…
Correct answer: Endothermic reaction- A. 11RT
- B. 4RT
- C. 5RT
- D. 7RT
Explanation: The formula of internal energy is U = (nRTf)/ 2where n = number of moles of the gas, f = number of degree of freedom.Keep in mind that…
Correct answer: 11RT