All Free Chemistry MCQs with Answers
Every Chemistry question in the bank, across all chapters, each with the correct answer and a written explanation. Free and unlimited, with no account needed.
13,720 questions · page 511 of 686
- A. One phase.
- B. Two phases.
- C. Three phases.
- D. Any number of phases.
Explanation: A heterogeneous system is one that contains two or more different phases.
Correct answer: Any number of phases.- A. ΔE = q + w
- B. ΔE = q - w
- C. ΔE = q + P ΔV
- D. ΔE = q + ΔH
Explanation: According to the first law of thermodynamics, the change in internal energy (ΔE) of a system is equal to the heat added to the system (q)…
Correct answer: ΔE = q - w- A. Extensive properties.
- B. Intensive properties.
- C. Physical properties.
- D. Chemical properties.
Explanation: The correct answer is Intensive properties. These are properties that do not depend on the amount of material present.
Correct answer: Intensive properties.- A. Intensive properties
- B. Extensive properties
- C. Physical properties
- D. None of the above
Explanation: The correct answer is Extensive properties. These are properties that change when the size of the sample changes.
Correct answer: Extensive properties- A. Surface tension and Viscosity.
- B. Pressure and Density.
- C. Melting and Boiling points.
- D. All of the above.
Explanation: The correct answer is Option D: All of the above. Intensive properties are characteristics of a substance that do not change with the…
Correct answer: All of the above.- A. Composition of the system.
- B. Temperature, Pressure & Volume.
- C. Refractive Index and specific heat.
- D. All of the above properties taken together.
Explanation: The correct answer is Option B: Temperature, Pressure & Volume. In thermodynamics, the state of a system is described by state variables…
Correct answer: Temperature, Pressure & Volume.- A. Isothermal process.
- B. Equilibrium process.
- C. Physical process.
- D. Chemical process.
Explanation: The correct answer is the 'Isothermal process'. In thermodynamics, an isothermal process is one in which the temperature of the system…
Correct answer: Isothermal process.- A. Enthalpy of atomization
- B. Enthalpy of fusion
- C. Enthalpy of vaporization
- D. Enthalpy of formation
Explanation: Option A, enthalpy of atomization, is the energy required to completely separate all the atoms in a chemical substance.
Correct answer: Enthalpy of atomization- A. Enthalpy change of formation of water
- B. Enthalpy change of neutralization
- C. Both; Enthalpy change of combustion of Hydrogen and enthalpy change of formation of water
- D. Enthalpy change of combustion of Hydrogen
Explanation: Since 1 mole of H2 is being combusted, it can be called enthalpy change of combustion of H2.
Correct answer: Both; Enthalpy change of combustion of Hydrogen and enthalpy change of formation of water- A. Enthalpy of combustion
- B. Enthalpy of formation
- C. Enthalpy of atomization
- D. Enthalpy of solution
Explanation: Combustion is an oxidation reaction that produces heat, and it is therefore always exothermic.
Correct answer: Enthalpy of combustion- A. The energy of activation of backward reaction is less than that of forward reaction
- B. The energy of activation of backward reaction is more that that of forward reaction
- C. The energy of activation of forward reaction is less than that of backward reaction
- D. The energy of activation of forward - backward reaction is same
Explanation: In an endothermic reaction, the activation energy of a forward reaction will always be greater than that of the reverse reaction as can be…
Correct answer: The energy of activation of backward reaction is less than that of forward reaction- A. Chemical Equilibrium
- B. Chemical Bonding
- C. Heat contents of a compound
- D. AlI of these options are correct
Explanation: This question has been repeated in multiple other papers, hence indicating that this is a high-yield concept.
Correct answer: Heat contents of a compound- A. -484 KJmol-1
- B. -242 KJmol-1
- C. -121 KJmol-1
- D. +242 KJmol-1
Explanation: To determine the enthalpy change of formation (ΔHf) for one mole of H2O, we can use the given information about the heat evolved in the…
Correct answer: -242 KJmol-1- A. Spontaneous reaction
- B. Non-Spontaneous reaction
- C. First law of thermodynamics
- D. All of the above options are correct
Explanation: In this case:Heat is being transferred from hot surroundings to the cold interior of a refrigerator, which is against the natural…
Correct answer: Non-Spontaneous reaction- A. Endothermic Reaction
- B. Non spontaneous Reaction
- C. Third Order Reaction
- D. Exothermic Reaction
Explanation: Calcium oxide reacts with water to form calcium hydroxide, also called slaked lime.
Correct answer: Exothermic Reaction- A. Joule's Law
- B. Ohm's Law
- C. Hess's Law
- D. Faraday's Law
- E. Boyle's Law
Explanation: Hess' law states that the change of enthalpy in a chemical reaction (i.e.
Correct answer: Hess's Law10217. In an adiabatic process:
- A. Pressure is maintained constant
- B. The gas is isothermally expanded
- C. There is perfect heat insulation
- D. System exchanges heat with the surroundings
Explanation: During an adiabatic process, the system is completely insulated from its surroundings.
Correct answer: There is perfect heat insulation- A. Heat of combustion
- B. Heat of formation
- C. Heat of solution
- D. Heat of dilution
Explanation: The enthalpy of reaction for any chemical reaction is equal to the difference between the sum of the enthalpies of the formation of the…
Correct answer: Heat of formation10219. The study of measurement of heat absorbed or given out in a chemical reaction is referred to as:
- A. Endothermic reaction
- B. Exothermic reaction
- C. Thermochemistry
- D. Heat of formation
Explanation: Thermochemistry is the branch of chemistry that deals with the measurement and analysis of heat energy changes in chemical processes and…
Correct answer: Thermochemistry- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: Since it is an endothermic process it takes heat from the surrounding making the temperature fall below room temperature.
Correct answer: Option B