Q. If the entropy of a system increases, what can be inferred about the spontaneity of the process?
-
A.
The process is non-spontaneous
-
B.
The process is spontaneous
-
C.
The process is at equilibrium
-
D.
None of the above
Solution
An increase in entropy indicates that the process is spontaneous, as per the second law of thermodynamics.
Correct Answer: B — The process is spontaneous
Learn More →
Q. If the entropy of a system increases, what is the effect on Gibbs Free Energy at constant temperature?
-
A.
ΔG increases
-
B.
ΔG decreases
-
C.
ΔG remains constant
-
D.
ΔG becomes zero
Solution
If entropy increases, ΔG decreases, making the reaction more favorable.
Correct Answer: B — ΔG decreases
Learn More →
Q. If the temperature of a system is increased, what happens to its entropy?
-
A.
It decreases
-
B.
It remains constant
-
C.
It increases
-
D.
It becomes zero
Solution
As the temperature of a system increases, the kinetic energy of the particles increases, leading to greater disorder and thus an increase in entropy.
Correct Answer: C — It increases
Learn More →
Q. If ΔG is negative for a reaction, what can be inferred about the reaction?
-
A.
The reaction is at equilibrium.
-
B.
The reaction is spontaneous.
-
C.
The reaction is non-spontaneous.
-
D.
The reaction requires energy input.
Solution
A negative ΔG indicates that the reaction is spontaneous.
Correct Answer: B — The reaction is spontaneous.
Learn More →
Q. If ΔG is negative for a reaction, what can be inferred?
-
A.
The reaction is non-spontaneous.
-
B.
The reaction is at equilibrium.
-
C.
The reaction is spontaneous.
-
D.
The reaction requires energy input.
Solution
A negative ΔG indicates that the reaction is spontaneous under the given conditions.
Correct Answer: C — The reaction is spontaneous.
Learn More →
Q. If ΔG is negative, what does it indicate about the reaction?
-
A.
Reaction is at equilibrium
-
B.
Reaction is spontaneous
-
C.
Reaction is non-spontaneous
-
D.
Reaction requires energy input
Solution
A negative ΔG indicates that the reaction is spontaneous.
Correct Answer: B — Reaction is spontaneous
Learn More →
Q. If ΔG is positive, what can be inferred about the reaction?
-
A.
The reaction is spontaneous.
-
B.
The reaction is at equilibrium.
-
C.
The reaction is non-spontaneous.
-
D.
The reaction will proceed in reverse.
Solution
If ΔG is positive, the reaction is non-spontaneous under the given conditions.
Correct Answer: C — The reaction is non-spontaneous.
Learn More →
Q. If ΔH = 100 kJ and ΔS = 0.2 kJ/K, what is ΔG at 298 K?
-
A.
100 kJ
-
B.
96 kJ
-
C.
104 kJ
-
D.
90 kJ
Solution
ΔG = ΔH - TΔS = 100 kJ - 298 K * 0.2 kJ/K = 100 kJ - 59.6 kJ = 40.4 kJ.
Correct Answer: B — 96 kJ
Learn More →
Q. If ΔH is negative and ΔS is positive, what can be said about ΔG?
-
A.
ΔG is always positive.
-
B.
ΔG is always negative.
-
C.
ΔG can be positive or negative depending on temperature.
-
D.
ΔG is zero.
Solution
If ΔH is negative and ΔS is positive, ΔG will always be negative, indicating that the reaction is spontaneous at all temperatures.
Correct Answer: B — ΔG is always negative.
Learn More →
Q. In a chemical reaction, if the enthalpy change is positive, the reaction is classified as:
-
A.
Exothermic
-
B.
Endothermic
-
C.
Isothermal
-
D.
Adiabatic
Solution
A positive enthalpy change indicates that the reaction absorbs heat, classifying it as endothermic.
Correct Answer: B — Endothermic
Learn More →
Q. In a chemical reaction, if the enthalpy of products is less than that of reactants, what can be concluded?
-
A.
The reaction is endothermic
-
B.
The reaction is exothermic
-
C.
The reaction is at equilibrium
-
D.
The reaction is spontaneous
Solution
If the enthalpy of products is less, the reaction releases heat, indicating it is exothermic.
Correct Answer: B — The reaction is exothermic
Learn More →
Q. In a closed system, if the temperature increases, what happens to the entropy?
-
A.
It decreases
-
B.
It increases
-
C.
It remains constant
-
D.
It becomes zero
Solution
In a closed system, an increase in temperature generally leads to an increase in entropy, as the molecular motion becomes more chaotic.
Correct Answer: B — It increases
Learn More →
Q. In a cyclic process, the net work done is equal to the:
-
A.
Change in internal energy
-
B.
Heat added to the system
-
C.
Heat removed from the system
-
D.
Net heat transfer
Solution
In a cyclic process, the net work done is equal to the heat added to the system.
Correct Answer: B — Heat added to the system
Learn More →
Q. In a reaction where ΔH is negative and ΔS is positive, what can be said about ΔG?
-
A.
ΔG is always negative.
-
B.
ΔG is always positive.
-
C.
ΔG is zero.
-
D.
ΔG depends on temperature.
Solution
If ΔH is negative and ΔS is positive, ΔG will always be negative at all temperatures.
Correct Answer: A — ΔG is always negative.
Learn More →
Q. In a reaction where ΔH is positive and ΔS is negative, what is the sign of ΔG at high temperatures?
-
A.
Positive
-
B.
Negative
-
C.
Zero
-
D.
Cannot be determined
Solution
At high temperatures, ΔG will be positive because the positive ΔH and negative ΔS will dominate the equation ΔG = ΔH - TΔS.
Correct Answer: A — Positive
Learn More →
Q. In a reversible process, the change in entropy of the universe is:
-
A.
Positive
-
B.
Negative
-
C.
Zero
-
D.
Undefined
Solution
In a reversible process, the change in entropy of the universe is zero, as the system and surroundings are in equilibrium.
Correct Answer: C — Zero
Learn More →
Q. In a reversible process, the change in Gibbs free energy (ΔG) is:
-
A.
Always positive
-
B.
Always negative
-
C.
Zero at equilibrium
-
D.
None of the above
Solution
In a reversible process, the change in Gibbs free energy (ΔG) is zero at equilibrium.
Correct Answer: C — Zero at equilibrium
Learn More →
Q. In a reversible process, the change in Gibbs free energy is equal to:
-
A.
Zero
-
B.
Enthalpy
-
C.
Entropy
-
D.
Temperature
Solution
In a reversible process at equilibrium, the change in Gibbs free energy is zero.
Correct Answer: A — Zero
Learn More →
Q. In a spontaneous process, the change in Gibbs free energy (ΔG) is:
-
A.
Positive
-
B.
Negative
-
C.
Zero
-
D.
Undefined
Solution
For a spontaneous process, the change in Gibbs free energy (ΔG) is negative.
Correct Answer: B — Negative
Learn More →
Q. In an endothermic reaction, the enthalpy of the products is ____ than that of the reactants.
-
A.
higher
-
B.
lower
-
C.
equal
-
D.
unpredictable
Solution
In an endothermic reaction, the enthalpy of the products is higher than that of the reactants.
Correct Answer: A — higher
Learn More →
Q. In an irreversible process, the change in entropy of the universe is:
-
A.
Zero
-
B.
Positive
-
C.
Negative
-
D.
Undefined
Solution
In an irreversible process, the change in entropy of the universe is positive, indicating that the total entropy increases.
Correct Answer: B — Positive
Learn More →
Q. In an isothermal process, the temperature of the system remains constant. What is the work done by the gas during expansion?
-
A.
Zero
-
B.
nRT ln(Vf/Vi)
-
C.
nRT (Vf - Vi)
-
D.
nR (Tf - Ti)
Solution
In an isothermal process, the work done by the gas is given by W = nRT ln(Vf/Vi).
Correct Answer: B — nRT ln(Vf/Vi)
Learn More →
Q. In thermodynamics, what does the term 'enthalpy' refer to?
-
A.
Internal energy plus pressure times volume
-
B.
Internal energy minus pressure times volume
-
C.
Heat content of a system
-
D.
Work done by a system
Solution
Enthalpy is defined as H = U + PV, where U is internal energy, P is pressure, and V is volume.
Correct Answer: A — Internal energy plus pressure times volume
Learn More →
Q. In which of the following reactions is the enthalpy change likely to be the largest?
-
A.
Dissolving salt in water
-
B.
Combustion of gasoline
-
C.
Melting of ice
-
D.
Sublimation of dry ice
Solution
The combustion of gasoline releases a large amount of energy, resulting in a large enthalpy change.
Correct Answer: B — Combustion of gasoline
Learn More →
Q. In which of the following reactions is the entropy change expected to be negative?
-
A.
N2(g) + 3H2(g) → 2NH3(g)
-
B.
C(s) + O2(g) → CO2(g)
-
C.
2H2(g) + O2(g) → 2H2O(g)
-
D.
CaCO3(s) → CaO(s) + CO2(g)
Solution
The reaction N2(g) + 3H2(g) → 2NH3(g) results in a decrease in the number of gas molecules, leading to a negative change in entropy.
Correct Answer: A — N2(g) + 3H2(g) → 2NH3(g)
Learn More →
Q. In which of the following scenarios is the entropy of the system likely to decrease?
-
A.
Ice melting
-
B.
Water freezing
-
C.
Gas expanding
-
D.
Liquid evaporating
Solution
The entropy of the system decreases when water freezes, as the molecules become more ordered in the solid state.
Correct Answer: B — Water freezing
Learn More →
Q. In which of the following scenarios is ΔG equal to ΔH?
-
A.
At high temperatures with ΔS = 0.
-
B.
At low temperatures with ΔS = 0.
-
C.
At constant pressure and temperature.
-
D.
In a phase transition.
Solution
During a phase transition, such as melting or boiling, ΔG equals ΔH because the system is at equilibrium.
Correct Answer: D — In a phase transition.
Learn More →
Q. In which of the following scenarios would the entropy of the system decrease?
-
A.
Ice melting
-
B.
Water evaporating
-
C.
Gas compressing
-
D.
Sugar dissolving in water
Solution
When a gas is compressed, the number of microstates decreases, leading to a decrease in entropy.
Correct Answer: C — Gas compressing
Learn More →
Q. In which process does the entropy of the system decrease?
-
A.
Freezing of water
-
B.
Evaporation of water
-
C.
Sublimation of dry ice
-
D.
Dissolving salt in water
Solution
The freezing of water results in a decrease in the entropy of the system as it transitions from liquid to solid.
Correct Answer: A — Freezing of water
Learn More →
Q. In which scenario would the Gibbs Free Energy of a system be at its minimum?
-
A.
At equilibrium
-
B.
At the start of a reaction
-
C.
At maximum temperature
-
D.
At maximum pressure
Solution
The Gibbs Free Energy of a system is at its minimum at equilibrium, indicating stability.
Correct Answer: A — At equilibrium
Learn More →
Showing 31 to 60 of 219 (8 Pages)
