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
Show solution
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
Show solution
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
Show solution
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.
Show solution
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.
Show solution
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
Show solution
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.
Show solution
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
Show solution
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.
Show solution
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
Show solution
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
Show solution
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
Show solution
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
Show solution
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.
Show solution
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
Show solution
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
Show solution
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
Show solution
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
Show solution
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
Show solution
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
Show solution
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
Show solution
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)
Show solution
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
Show solution
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
Show solution
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)
Show solution
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
Show solution
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.
Show solution
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
Show solution
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
Show solution
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
Show solution
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)
Thermodynamics MCQ & Objective Questions
Thermodynamics is a crucial topic in physics that plays a significant role in various school and competitive exams. Understanding the principles of thermodynamics not only enhances your conceptual clarity but also boosts your confidence in solving MCQs. Practicing thermodynamics MCQ questions and objective questions can help you identify important questions and improve your exam preparation effectively.
What You Will Practise Here
Basic concepts of thermodynamics including laws and definitions
Key formulas related to heat, work, and energy
Understanding of thermodynamic processes: isothermal, adiabatic, and isochoric
Applications of the first and second laws of thermodynamics
Concepts of entropy and its significance in thermodynamic systems
Diagrams illustrating thermodynamic cycles and processes
Real-world applications of thermodynamics in engineering and science
Exam Relevance
Thermodynamics is a vital topic in various examinations such as CBSE, State Boards, NEET, and JEE. Questions often focus on the application of laws, problem-solving using formulas, and conceptual understanding. Common question patterns include numerical problems, theoretical questions, and application-based scenarios, making it essential for students to grasp the core concepts thoroughly.
Common Mistakes Students Make
Confusing the different thermodynamic processes and their characteristics
Misapplying the laws of thermodynamics in problem-solving
Overlooking units and conversions in calculations
Neglecting the significance of entropy and its implications
Failing to interpret diagrams correctly in relation to thermodynamic cycles
FAQs
Question: What are the three laws of thermodynamics?Answer: The three laws of thermodynamics are the Zeroth Law, which defines thermal equilibrium; the First Law, which is the law of energy conservation; and the Second Law, which introduces the concept of entropy.
Question: How can I improve my understanding of thermodynamics for exams?Answer: Regular practice of thermodynamics MCQ questions, reviewing key concepts, and solving previous years' papers can significantly enhance your understanding and performance.
Start solving thermodynamics practice MCQs today to test your understanding and prepare effectively for your exams. Mastering this topic will not only help you score better but also build a strong foundation for future studies in physics.
