Chemistry · Physics

Thermodynamics and Chemical Kinetics

1,132 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

Multiple choice chemistry chemical equilibrium relationship between equilibrium constant, reaction quotient and gibbs energy law of mass action chemical equilibrium and acids-bases

When reaction is at standard state at equilibrium, then:

  1. $\Delta H^\circ\, =\, 0$
  2. $\Delta S^\circ\, =\, 0$
  3. equilibrium constant $K = 0$
  4. equilibrium constant $K = 1$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

If $K$ is equal to 1, the reaction will reach equilibrium as an intermediate mixture, meaning the amounts of products and reactants will be about the same.

Multiple choice applications of adsorption adsorption adsorption and colloids surface chemistry chemistry

Which is not correct regarding the adsorption of a gas on surface of a solid?

  1. On increasing temp. adsorption increase continuously

  2. Enthalpy & entropy change is Ve

  3. Adsorption is more for some specific substance

  4. Reversible
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Adsorption of gas $\propto$ $\dfrac{1}{temperature}.$
Thus, as the temperature of the gas increases, the gas molecule gets energy and leave the surface. Thus, the rate of adsorption decreases with increase in temperature.
Multiple choice physics heat energy transfers heat energy heat, internal energy and work internal energy

Amount of heat energy present is determined by :

  1. Sum total of kinetic energy and the potential energy of its molecules

  2. Sum total of mechanical energy and surface energy of its molecules

  3. Sum total of chemical energy and potential energy of its molecules

  4. All
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The amount of heat energy present in a body is determined by the sum total of the kinetic energy and potential energy of its molecules.

Multiple choice physics heat energy transfers heat energy heat, internal energy and work internal energy

When heat energy is given out by a hot substance then the kinetic energy of its molecules _________. Fill in the blank. 

  1. Increases

  2. Decreases

  3. Remain same

  4. None
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When heat energy is given out by a hot substance, the internal energy of the substance decreases hence kinetic energy of its molecules i.e. they become slower in motion.

Multiple choice physics heat energy transfers heat energy heat, internal energy and work internal energy

At the molecular level what can be said about Heat energy?

  1. Heat energy is equal to total mechanical energy of all its molecules

  2. Heat energy is equal to total potential energy of all its molecules

  3. Heat energy is equal to total kinetic energy of all its molecules

  4. Heat energy is equal to total heat energy of all its molecules
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

At molecular level, heat energy is equal to mechanical energy of all molecules. Mechanical energy of the molecules is the sum of total Kinetic energy and potential energy of molecules.

Multiple choice chemistry phenomena around us changes and its classification types of changes classification of changes

Which of the following is true?

  1. A physical change can never be reversible.

  2. A chemical change can never be reversible.

  3. Both of the above

  4. A physical change may be reversible.
    Also, a chemical change may be reversible.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A physical change may be reversible. For example, melting of ice is a reversible change.
Also, a chemical change may be reversible. For example, the reaction between $\displaystyle N _2$ and $\displaystyle H _2$ to form $\displaystyle NH _3$ is a reversible chemical change.

Multiple choice chemistry phenomena around us changes and its classification types of changes classification of changes

Choose the incorrect statement(s).

  1. Chemical reactions are characterized by the change in colour.

  2. Chemical reactions are not alone characterized by change in state.

  3. Physical changes are characterized by the change in colour of reacting substances.

  4. Physical changes are not reversible.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Physical changes are generally reversible (e.g., melting ice), whereas chemical changes are generally irreversible. Therefore, the statement that physical changes are not reversible is incorrect.

Multiple choice chemistry phenomena around us changes and its classification types of changes classification of changes

Cooking of rice is an example of:

  1. irreversible change

  2. endothermic reaction
  3. both $A$ & $B$

  4. none of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Cooking of rice is both irreversible and endothermic reaction. i.e once cooked rice cannot be made rice back and the rice absorbs heat from the external sources and utilizes for its cooking so it is endothermic.

Multiple choice chemistry phenomena around us changes and its classification types of changes classification of changes

If two substances interact to produce a change, they will do so:

  1. under any condition

  2. no matter what kind of interaction there is

  3. only if the interaction is of the right kind and under the right conditions

  4. only if they are in close contact with each other
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

According to transition state theory, two molecules interact with each other when they are aligned in a proper orientation.

Hence, two substance interact to produce a change only if the interaction is of the right kind under right conditions.

Multiple choice physics types of energy law of conservation of energy the law of conservation of energy work, energy and machines

Energy conservation law says that:

  1. Energy can't be destroyed but can be produced.

  2. Neither energy can be produced nor can be destroyed.

  3. Energy can't be produced but can be destroyed.

  4. Energy can be produced and can be destoyed
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In physics, the law of conservation of energy states that the total energy of an isolated system remains constant—it is said to be conserved over time. Energy can neither be created nor destroyed; rather, it transforms from one form to another.

Multiple choice physics types of energy law of conservation of energy the law of conservation of energy work, energy and machines

According to law of conservation of energy :

  1. Energy can be created but not destroyed and it can be transformed from one form into another

  2. Energy exists in only one form

  3. Energy exists in many forms but it cannot be transformed

  4. Energy can neither be created nor be destroyed but can change into different forms
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The law of conservation of energy states that in a closed system the total amount of energy is conserved and does not change. This means that energy may change from one form to another, but that the total amount of energy in the closed system remains constant. 

So accoding to this statement it is clear that only option D is best possible.

Multiple choice physics types of energy law of conservation of energy the law of conservation of energy work, energy and machines

What is law of conservation of energy?

  1. Energy can neither be created nor destroyed. It can only be transformed from one to another.

  2. Energy can only be created nor destroyed. It can only be transformed from one to another.

  3. Energy can neither be created but can be destroyed. It can only be transformed from one to another.

  4. None
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Energy can neither be created nor destroyed. It can only be transformed from one to another is the law of conservation of energy. For example , object falling from certain height converts its potential energy to kinetic energy and at all instant total mechanical energy remains constant.