1. Which law of thermodynamics introduces the concept of entropy?
Answer:
Explanation:
The second law of thermodynamics introduces the concept of entropy, stating that in all energy transfers, the potential energy of the final state will be less than that of the initial state.
2. Which of the following is an extensive property?
Answer:
Explanation:
Extensive properties depend on the amount of matter present. Entropy, being dependent on the amount, is an extensive property.
3. The enthalpy change for a reaction that occurs at constant pressure and releases energy is:
Answer:
Explanation:
Exothermic reactions release energy, resulting in a negative enthalpy change.
4. Which of the following processes is spontaneous?
Answer:
Explanation:
Ice melting at room temperature happens spontaneously as it tends to increase entropy.
5. The internal energy of an isolated system is:
Answer:
Explanation:
For an isolated system, there is no exchange of energy or matter with the surroundings, hence its internal energy remains constant.
6. What does the first law of thermodynamics state?
Answer:
Explanation:
The first law of thermodynamics is essentially the law of conservation of energy.
7. The efficiency of a Carnot engine operating between temperatures T1 and T2 is given by:
Answer:
Explanation:
The efficiency of a Carnot engine is given by (T2-T1)/T1 where T2 > T1.
8. Gibbs free energy (G) is given by:
Answer:
Explanation:
Gibbs free energy relates enthalpy, entropy, and temperature of a system: G = H – TS.
9. A reaction with positive enthalpy and positive entropy change is spontaneous at:
Answer:
Explanation:
A reaction with positive ΔH and positive ΔS will be spontaneous at high temperatures according to the Gibbs free energy equation.
10. An adiabatic process is one in which:
Answer:
Explanation:
In an adiabatic process, the system does not exchange heat with its surroundings.
11. The zeroth law of thermodynamics deals with:
Answer:
Explanation:
The zeroth law establishes the concept of thermal equilibrium and forms the basis for temperature measurement.
12. Which law states that the entropy of a perfect crystal is zero at absolute zero temperature?
Answer:
Explanation:
The third law of thermodynamics states that a perfect crystal has an entropy of zero at absolute zero temperature.
13. Isothermal expansion of an ideal gas is:
Answer:
Explanation:
Isothermal expansion of an ideal gas at a constant temperature can be carried out reversibly.
14. If the entropy change of a system and surroundings is zero, the process is:
Answer:
Explanation:
For a process to be reversible, the total entropy change of the system and its surroundings should be zero.
15. The measure of randomness or disorder of a system is termed as:
Answer:
Explanation:
Entropy is a measure of the randomness or disorder of a system.
16. A process carried out at constant volume is called:
Answer:
Explanation:
An isochoric process is one that occurs at constant volume.
17. The change in Gibbs free energy at equilibrium is:
Answer:
Explanation:
At equilibrium, the change in Gibbs free energy (ΔG) is zero.
18. Which of the following statements about a spontaneous process is true?
Answer:
Explanation:
For a spontaneous process, the change in Gibbs free energy (ΔG) is always negative.
19. The heat capacity at constant pressure (Cp) minus the heat capacity at constant volume (Cv) for an ideal gas is equal to:
Answer:
Explanation:
For an ideal gas, Cp – Cv = R, where R is the universal gas constant.
20. Which of the following is a state function?
Answer:
Explanation:
State functions are properties that depend only on the state of the system and not on the path taken to reach that state. Internal energy is a state function.