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

Potential energy is also known as

  1. stored energy

  2. rotational energy

  3. K. E.

  4. none of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Potential energy is the energy held by an object because of its position relative to other objects, stresses within itself, or its electric charge; it is often referred to as stored energy.

Multiple choice

Which of the following statements is/are correct?

A. Certain chemical reactions are driven by light. R. Light may supply required energy to drive the reaction.

  1. Both A and R are true and R is the correct explanation of A.

  2. Both A and R are true but R is not the correct explanation of A.

  3. A is true but R is false.

  4. A is false but R is true.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Certain chemical reactions are driven by light as light may supply required energy to drive the reaction.

Multiple choice

For which of the following reactions ∆H is equal to ∆U?

  1. <span style="font-size:11.0pt;line-height:115%;font-family:"Calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:Calibri;mso-fareast-theme-font:minor-latin;mso-hansi-theme-font:minor-latin;mso-bidi-theme-font:minor-latin;mso-ansi-language:EN-US;mso-fareast-language:EN-US;mso-bidi-language:AR-SA">H2(g) + I2(g) → 2HI(g)

  2. <span style="font-size:11.0pt;line-height:115%;font-family:"Calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:Calibri;mso-fareast-theme-font:minor-latin;mso-hansi-theme-font:minor-latin;mso-bidi-theme-font:minor-latin;mso-ansi-language:EN-US;mso-fareast-language:EN-US;mso-bidi-language:AR-SA">H2(g) + 1/2O2(g) → H2O(l)

  3. <span style="font-size:11.0pt;line-height:115%;font-family:"Calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:Calibri;mso-fareast-theme-font:minor-latin;mso-hansi-theme-font:minor-latin;mso-bidi-theme-font:minor-latin;mso-ansi-language:EN-US;mso-fareast-language:EN-US;mso-bidi-language:AR-SA">2SO3(g) → 2SO2(g) +O2(g)

  4. <span style="font-size:11.0pt;line-height:115%;font-family:"Calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:Calibri;mso-fareast-theme-font:minor-latin;mso-hansi-theme-font:minor-latin;mso-bidi-theme-font:minor-latin;mso-ansi-language:EN-US;mso-fareast-language:EN-US;mso-bidi-language:AR-SA">2NO2(g) → N2O4(g)
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The correct relation between ∆H and ∆U is given by the relation ∆H = ∆U +∆ngRT…………..where ∆ng is the difference in number of moles of gaseous products and reactants. For the given reaction ∆ng = (2-[1+1]) = 0, so ∆H = ∆U.

Multiple choice

Which of the following statements is/are false?

a. Some chemical substances can be obtained in pure state by the process of crystallisation. b. The product formed when a substance dissolves in a liquid is known as a solution. c. In a chemical reaction, the substances responsible for bringing about a chemical change are called products.

  1. Only a

  2. Only a and b

  3. Only b

  4. Only b and c

  5. Only c
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This is the correct option as this statement is false. In a chemical reaction, the substances responsible for bringing about a chemical change are called reactants.

Multiple choice

Which of the following is not a property of a chemical change?

  1. Changes are temporary and reversible.

  2. Changes are followed by the formation of a new product.

  3. Changes may give out or absorb heat, light or sound.

  4. Changes are followed by the change in state and composition.

  5. Changes may be followed by the change in colour.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This is the correct option as this is not a property of a chemical change. Changes are permanent and irreversible.

Multiple choice

Which of the following is not studied under physical chemistry?

  1. Energy changes in a reaction

  2. Reaction rate

  3. Effect of electricity on chemical reaction

  4. Percentage composition of each element in a compound
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Physical chemistry focuses on the physical properties and behavior of matter, such as energy, reaction rates, and electrical effects. Percentage composition is typically studied in analytical chemistry.

Multiple choice

In negative deviation from Rault's law:

  1. A-A interactions = B-B interactions = A-B interactions.

  2. A-A interactions = B-B interactions # A-B interactions.

  3. A-B interactions are more than that of A-A and B-B.

  4. A-B interactions are less than A-A and B-B.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

ANS 3.

Multiple choice

Temperature is a measure of ___________.

  1. total kinetic energy of molecules

  2. total potential energy of molecules

  3. average potential energy of molecules

  4. average kinetic energy of molecules
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Temperature is a measure of the average heat or thermal energy of the particles in a substance. Since it is an average measurement, it does not depend on the number of particles in an object. In that sense it does not depend on the size of it. For example, the temperature of a small cup of boiling water is the same as the temperature of a large pot of boiling water. Even if the large pot is much bigger than the cup and has millions and millions more water molecules.

Multiple choice

Chemical changes are __________.

  1. temporary, reversible and a new substance is produced

  2. always accompanied by exchange of light

  3. permanent, irreversible and a new substance is produced

  4. never accompanied by exchange of light and heat energy
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

 factual

Multiple choice

Temperature is a measure of ___________.

  1. total kinetic energy of molecules

  2. total potential energy of molecules

  3. average potential energy of molecules

  4. average kinetic energy of molecules
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Temperature is a measure of the average heat or thermal energy of the particles in a substance. Since it is an average measurement, it does not depend on the number of particles in an object. In that sense it does not depend on the size of it. For example, the temperature of a small cup of boiling water is the same as the temperature of a large pot of boiling water. Even if the large pot is much bigger than the cup and has millions and millions more water molecules.

Multiple choice

Energy can be neither created nor destroyed, but can be changed from one form to another.

Which of the following statements does not support the above conclusion?

  1. When energy in one form disappears, an equivalent amount of energy in other forms appears somewhere.

  2. The law of conservation applies only when the quantity of matter remains the same.

  3. This law is responsible for a passenger in a running bus moving forward suddenly when the bus stops.

  4. When a bus starts, a standing passenger tends to remain firm rather than the squatting passenger.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

No transformation is taking place here.