Chemistry · Physics
Thermodynamics and Chemical Kinetics
1,092 Questions
Thermodynamics and chemical kinetics are crucial branches of physical chemistry. This area focuses on energy transformations, reaction rates, equilibrium constants, and catalysts. These topics carry significant weight in competitive science and engineering examinations.
Enthalpy and energyChemical equilibriumEntropy conceptsReaction kinetics and catalysts
Thermodynamics and Chemical Kinetics Questions
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Number of defects increase exponentially
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Number of defects increase linearly
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Number of defects increase following quadratic equation
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None
D
Correct answer
Explanation
As Process Sigma increases, the number of defects decreases exponentially, not increases. Higher sigma means better process capability with fewer defects. Option D 'None' is correct because all other options incorrectly state that defects increase. At 6 sigma, defects are extremely low (3.4 per million opportunities).
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When Data is discrete, we can use DPMO method
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When data is continuous and normal, we can use area under the curve method
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When Data is discrete, we can use area under the curve method
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Zst = Zlt + 1.5
C
Correct answer
Explanation
Process sigma calculations use different methods depending on data type. For discrete data, DPMO (Defects Per Million Opportunities) is the appropriate method. For continuous data that follows a normal distribution, the area under the normal curve method is used. Option C incorrectly suggests using area under curve for discrete data, which is not standard practice - discrete data requires DPMO or similar discrete methods. Option D correctly states the Z shift formula.
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isothermal
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adiabatic
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isobar
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none of above
B
Correct answer
Explanation
An adiabatic process is one in which no heat is exchanged between a system and its surroundings (Q=0). An isothermal process occurs at constant temperature, and an isobaric process occurs at constant pressure. The question phrasing 'process of constant heat' refers to the lack of heat transfer.
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U1-2 = W + Q
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W = Q + U1-2
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Q = U1-2 + W
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Q = U1-2 -W
C
Correct answer
Explanation
The First Law of Thermodynamics states energy is conserved: heat added to a system equals its change in internal energy plus work done BY the system. Option C correctly expresses this as Q = ΔU + W, where W represents work output. Options A and B incorrectly arrange terms, while D would only be valid if W represented work done ON the system (opposite sign convention).
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Zeroth law of ThermoDynamics
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First law of ThermoDynamics
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second law of ThermoDynamics
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Third law of ThermoDynamics
A
Correct answer
Explanation
This is the Zeroth Law of Thermodynamics, which defines thermal equilibrium and forms the basis for temperature measurement. The First Law is energy conservation, Second Law governs entropy and spontaneous processes, and Third Law concerns absolute zero.
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Zeroth law of thermodynamics
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First law of thermo Dynamics
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Second law of thermoDynamics
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Third law of thermodynamics
A
Correct answer
Explanation
The Zeroth law of thermodynamics states that if two systems are in thermal equilibrium with a third system, they are in thermal equilibrium with each other. This establishes thermal equilibrium as a transitive relation, which is fundamental to temperature measurement.
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Zeroth law of thermodynamics
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First law of thermo Dynamics
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Second law of thermoDynamics
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Third law of thermodynamics
D
Correct answer
Explanation
The Third Law of Thermodynamics states that it's impossible to reach absolute zero (0 Kelvin) in a finite number of operations. As temperature approaches absolute zero, the entropy change approaches zero, making complete cooling unachievable.
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Zeroth law of thermodynamics
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First law of thermo Dynamics
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Second law of thermoDynamics
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Third law of thermodynamics
B
Correct answer
Explanation
The First Law of Thermodynamics is the law of conservation of energy - energy can neither be created nor destroyed, only transformed from one form to another.
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Constant enthalpy
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Constant pressure
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Constant temparature
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Constant Entropy
D
Correct answer
Explanation
An isentropic process is a reversible adiabatic process in which entropy remains constant throughout. 'Iso' means constant and 'tropic' refers to entropy.
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Constant enthalpy
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Constant pressure
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Constant temparature
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Constant Pressure
D
Correct answer
Explanation
An isobaric process is a thermodynamic process where pressure remains constant throughout. 'Iso' means constant and 'baric' refers to pressure (bar is a pressure unit).
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Zeroth law of thermodynamics
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First law of thermo Dynamics
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Second law of thermoDynamics
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Third law of thermodynamics
C
Correct answer
Explanation
The Second Law of thermodynamics states that heat cannot be completely converted into work in a cyclic process without any other effect. There's always some waste heat that must be rejected to a colder reservoir, establishing limits on thermal efficiency.
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Vey high Specific heat capacity
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Poor conductor of heat
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None of the obove
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Both of the above
D
Correct answer
Explanation
Water's effectiveness as a coolant comes from two key properties: very high specific heat capacity (absorbs large heat energy with small temperature rise) and poor thermal conductivity (heat doesn't quickly transfer back). This dual nature makes water ideal for cooling systems. Neither property alone would be as effective.
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entropy decreases
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entropy increases
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entropy remains unchanged
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entropy varies exponentially
B
Correct answer
Explanation
When hot liquid mixes with cold liquid, heat flows from the higher temperature region to the lower temperature region until thermal equilibrium is reached. This mixing process increases the overall entropy of the system because the energy becomes more dispersed and the system moves toward a more disordered state.
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enthalpy
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entropy
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temperature
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pressure
A
Correct answer
Explanation
In a throttling process (also known as Joule-Thomson expansion), the enthalpy remains constant. This is an isenthalpic process where a fluid expands from high pressure to low pressure through a valve or porous plug without doing external work or heat transfer. Entropy typically increases during throttling.