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

Calorific value of a fuel is

  1. time needed for one kilogram of fuel to be burnt out completely

  2. change in state of the fuel

  3. time needed for half kilogram of fuel to be burnt out completely

  4. amount of heat energy produced on complete combustion of one kilogram of fuel

  5. heat energy needed to burn the fuel
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The amount of heat energy produced on complete combustion of one kilogram of fuel is called its calorific value.

Multiple choice

Which of the following statements is true about physical and chemical changes?

  1. During a chemical change, the reactants form the products with equal mass.

  2. The physical changes can not be reversed.

  3. The chemical changes can be reversed.

  4. In physical changes, a new substance is formed and energy is either given off or absorbed.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Chemical change is any change that results in the formation of a new chemical substance. It involves making and breaking the bonds between atoms. It cannot be reversed. Physical change is affecting the form of a chemical substance, but not its chemical composition. It can be reversed. 

Multiple choice

Enzymes are able to accelerate a reaction because ___________.

  1. reacting substances are brought into highly specific relations with each other

  2. energy is added to the system

  3. molecules of the reactants are speeded up so that random encounters are more

  4. products of the reaction are removed simultaneously

  5. metallic ions are absent in the protein molecules
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Enzymes are able to accelerate a reaction because reacting substances are brought into highly specific relations with each other.

Multiple choice

Which of the following statements about chemisorption is not true?

  1. Adsorbate molecules are bound to the surface of adsorbent by chemical bonds.

  2. Chemisorption is an endothermic process.

  3. This process increases with increase in surface area of the adsorbent.

  4. This process is highly specific in nature.

  5. It is also known as activated adsorption.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Chemisorption is an exothermic process.

Multiple choice

STATEMENT 1: In Haber's process synthesis of NH3 I carried out in presence of catalyst. STATEMENT 2: The catalyst shifts the position of equilibrium of reaction to products side.

  1. <span style="sans-serif=">Statement 1 is true, statement 2 is true and statement 2 is correct explanation of statement 1

  2. <span style="sans-serif=">Statement 1 is true, statement 2 is true but statement 2 is not correct explanation of statement 1

  3. <span style="sans-serif=">Statement 1 is true, statement 2 is false

  4. <span style="sans-serif=">Statement 1 is false, statement 2 is true
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This answer is correct because it is true that we use a catalyst to carry out Haber's process but it is the property of a catalyst that it does not alter the equilibrium position but provides an alternative path for the reaction.

Multiple choice

If N2 + 3H2 ⇌ 2NH3 is a reversible reaction, then

  1. increase in pressure will favour forward reaction

  2. increase in pressure will favour backward reaction

  3. equilibrium remains undisturbed on increasing pressure

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

An increase in pressure will favour the direction where there is lesser number of species.

Multiple choice

Which of the following is NOT the characteristic of equilibrium?

  1. Dynamic in nature

  2. Non-spontaneous

  3. Reversible

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

This option is correct because equilibrium is always spontaneous. Being spontaneous means that the reaction proceeds with any external help or external driving force such as temperature of pressure.

Multiple choice

Consider a reaction for which enthalpy change (∆H0) is zero. The equilibrium constant will

  1. increase on increasing temperature

  2. decrease on increasing temperature

  3. first decrease then increase on increasing temperature

  4. be independent of temperature.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

This option is correct because for a reaction having enthalpy change zero is independent of change of temperature and favors neither formation of products or reactants.

Multiple choice

Directions: The following question has four choices out of which ONLY ONE is correct.

The effect of the change in external conditions on the chemical equilibrium is given by

  1. Le- Chatelier’s principle

  2. Hardy Shulze Rule

  3. Markovnikov's Rule

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

This is the correct answer because the external effects on equilibrium were given by chemist Henry Louis Le Chatelier. Hence it is called Le Chatelier’s principle. According to Le Chatelier’s Principle when a system is subjected to any disturbance in its equilibrium state then equilibrium is shifted in the direction where the effect of the change in external condition is minimized.

Multiple choice

At chemical equilibrium or in phase equilibrium, the total sum of which property becomes zero as free energy is at the minimum?

  1. Viscocity

  2. Surface tension

  3. Chemical potential

  4. Heat capacity

  5. Electrical resistivity
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In thermodynamics, chemical potential, also known as partial molar free energy, is a form of potential energy that can be absorbed or released during a chemical reaction. It may also change during a phase transition.