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 equilibrium in physical processes introduction to equilibrium chemical equilibrium and acids-bases

Which of the following is not a general characteristic of equilibrium involving physical processes ?

  1. equilibrium is possible only in a closed system at a given temperature .

  2. all measurable properties of the system remain constant .

  3. all the physical processes stop at equilibrium.

  4. the opposing processes occur at the same ratio and there is dynamic but stable condition .
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Equilibrium is a dynamic process, not a static one. Even at equilibrium, the forward and backward processes continue to occur at the same rate; they do not stop.

Multiple choice chemistry atomic theory, periodic classification and properties of elements introduction to periodic table necessity of classification need for classification

Catalyst in a reaction:

  1. lower the activation energy

  2. increases the activation energy

  3. increases the rate of reaction

  4. both A and C
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A catalyst increases the rate of a reaction by providing an alternative pathway with a lower activation energy. Since both statements A and C are correct, D is the correct choice.

Multiple choice chemistry chemical kinetics introduction to chemical kinetics understanding chemical kinetics rate of chemical reaction

Chemical kinetics a branch of physical chemistry deals with:

  1. structure of molecules

  2. heat changes in a reaction

  3. physical changes in a reaction

  4. rate of reactions
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Chemical kinetics is branch of physical chemistry that is concerned with understanding the rates of chemical reactions.

Structures and physical changes are deal in solid state and while studying liquids.

Thermochemistry deals with energy changes in chemical reactions.


Multiple choice chemistry chemical kinetics introduction to chemical kinetics understanding chemical kinetics rate of chemical reaction

Which of the following theory is not related to the chemical kinetics?

  1. Collision theory

  2. Absolute theory

  3. Absolute reaction rate

  4. VSEPR theory
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Valence shell electron pair repulsion (VSEPR) theory is a model used in chemistry to predict the geometry of individual molecules from the number of electron pairs surrounding their central atoms.

It's not related to the chemical kinetics.

Multiple choice chemistry chemical kinetics introduction to chemical kinetics understanding chemical kinetics rate of chemical reaction

Chemical kinetics, a branch of physical chemistry, deals with:

  1. heat changes in a reaction

  2. physical changes in a reaction

  3. rate of reactions

  4. structure of molecules
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Chemical word is related to reaction and kinetics is related to speed or rate, hence in chemical kinetics we study rate of reaction.

Multiple choice chemistry chemical reactions and equations introduction to chemical kinetics understanding chemical kinetics rate of chemical reaction

Which statements are correct in terms of chemical kinetic stuides?

  1. The quenching of a reaction can be made by cooling the reaction mixture.

  2. The quenching of a reaction can be made by diluting the reaction mixture.

  3. The reaction is supposed to be completed if it is kept for long time or strongly heated.

  4. None of the above
Reveal answer Fill a bubble to check yourself
A,B,C Correct answer
Explanation

The quenching of a reaction can be made by cooling as well as diluting the reaction mixture. The reaction is supposed to be completed if it is kept for a long time or strongly heated. Quenching a reaction is used to deactivate any unreacted reagents. It is also done by adding an antisolvent to induce precipitation, and collecting or removing the solids.

Multiple choice chemistry chemical kinetics introduction to chemical kinetics understanding chemical kinetics rate of chemical reaction

What does the exponential factor represent?

  1. The total number of reactants in a reaction.

  2. The amount of energy needed to start a chemical reaction.

  3. The fraction of reactants that have approached the activation energy hill and made it over per number of attempts.

  4. The fraction of reaction energy given off per unit of time.

  5. The fraction of products that have approached the activation energy hill and made it over per number of attempts.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The exponential factor represents the fraction of "reactants" that have approached the activation energy hill and made it over per number of attempts.

Multiple choice chemistry chemical kinetics introduction to chemical kinetics understanding chemical kinetics rate of chemical reaction

The study of chemical kinetics becomes highly complicate if there occurs:

  1. reversible reaction

  2. side reaction

  3. surface reaction

  4. none of these
Reveal answer Fill a bubble to check yourself
B,C Correct answer
Explanation

The study of chemical kinetics becomes highly complicate if there occurs side reactions or surface reactions.These reactions bring changes in the value of rate constant and not help to proceeds the reaction in the right manner.

Multiple choice chemistry changes around us can all changes be reversed? substances and objects classification of changes

Which of the following is true about dissolving:

  1. Dissolving is an example of a reversible change.

  2. Dissolving is an example of a irreversible change.

  3. It depends on the conditions of dissolution.

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

Dissolving is an example of a reversible change. When salt is mixed with water it disappears because it dissolves in the water to make salty water. But we can get the salt can back again by boiling off the water. That leaves the salt behind.

Multiple choice biology physical resources air as a natural resource types of chemical reactions chemical reactions

Why is respiration considered an exothermic reaction ? Explain.

  1. reduction of glucose takes place

  2. produces large amount of heat energy.

  3. oxidation of glucose takes place

  4. All of the above
Reveal answer Fill a bubble to check yourself
B,C Correct answer
Explanation

Energy is required to support life. Energy in our body is obtained from the food we eat. During digestion, large molecules of food are broken down into simpler substances such as glucose. Glucose combines with oxygen in the cells and provides energy. The special name of this combustion reaction is respiration. Since energy is released in the whole process, it is an exothermic process.
$\underset{Glucose}{C _6H _{12}O _6(aq)} + \underset{Oxygen}{6O _2(g)} \rightarrow \underset{Carbon dioxide}{6CO _2(g)} + \underset{Water}{6H _2O(l)} + Energy$

Multiple choice chemistry chemical reactions of organic compounds combustion and thermal cracking of hydrocarbons chemical properties of carbon compounds chemical properties of organic compounds

A chemical process in which a substance reacts with oxygen to give off heat is______?

  1. respiration

  2. combustion

  3. explosion

  4. conduction
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A chemical process in which a substance reacts with oxygen to give off heat is combustion.
For example, when C is burnt in excess air, it gives carbon dioxide and heat.
$\displaystyle C + O _2 \rightarrow CO _2 + $ heat

Multiple choice chemistry oxidation- reduction reactions redox reactions and electrode processes redox and electrode processes applications of redox reaction

Daniel cell operates under nonstandard state conditions. If the equation of the cell reaction is multiplied by 2 then:

  1. $E$ and $E^o$ remain unchanged
  2. $E$ is doubled
  3. $n$ remains unchanged in Nernst equation
  4. $Q$ is halved in Nernst equation
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Nernst's equation states ${ E } _{ cell }={ E } _{ cell }^{ 0 }+\dfrac { RT }{ nF } ln\left[ { M }^{ + } \right] $

Where $E$ and ${ E }^{ 0 }$ of cell are independent of volume/quantity of reacting species in electrolyte, they are intunsic properties of cell. Hence, on doubling cell equation of Daniel cell.
$Zn\left| { Zn }^{ 2+ } \right| \left| { Cu }^{ 2+ } \right| Cu$,
its e.m.f $(E)$ and standard e.m.f $\left( { E }^{ 0 } \right) $ remain unchanged where ${ E }^{ 0 }$ stays at $1.09V$.

Multiple choice chemistry energy fuel cell fuel cells electrochemistry, rechargeable batteries, and fuel cells

Which of the following statements is true for fuel cells ?

  1. They are more efficient

  2. They are free from pollution

  3. They run till reactants are active

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The fuel cells are more efficient. The energy efficiency of fuel cells is around 70 %. The only reaction product is water. Hence the fuel cells are free from pollution. The reactants are continuously supplied from external source. Hence fuel cells run till reactants are active.