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

Multiple choice physics the essence of change forms of energy and energy conservation energy for everything forms of energy

Identify, which of the following energies can be positive only

  1. kinetic energy

  2. potential energy

  3. mechanical energy

  4. both kinetic and mechanical energies
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Only kinetic energy can have positive value. Potential energy has negative value and mechanical energy is combination of these two hence can either be positive or negative.

Multiple choice physics the essence of change forms of energy and energy conservation energy for everything forms of energy

Energy stored in the bonds of molecules is a form of:

  1. heat energy

  2. potential energy'

  3. chemical energy

  4. light energy
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The Energy that gets released when the bonds are formed was stored in the electromagnetic fields inside of the atom. When the bond is formed, the electrons and protons assume a configuration that has an, overall, less intense combination of electric and magnetic fields inside of the bonded atoms than when they were separate. 

Multiple choice chemistry energetics and thermochemistry bond energies and enthalpy changes bond enthalpies enthalpies for different types of reactions

The incorrect statement is :

  1. $ \Delta _{ So| }H^{ 0 }={ \Delta } _{ Lattice }H^{ 0+ }\Delta _{ Hyd }H^{ 0 } $

  2. The enthalpy on dilution is independent on original concentration.
  3. $ N \equiv N > C \equiv N > C \equiv C $ [value of mean bond enthalpy in KJ/mol]
  4. $ H _2O(S) \overset { 1\quad bar }{ \rightleftharpoons } H _2O(I) 273 K $


    $ \Delta U= +Ve; \Delta H = +ve; W= +ve; q = +ve $
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The statement about dilution enthalpy is incorrect because enthalpy of dilution DOES depend on the original concentration of the solution. Dilution from different starting concentrations releases different amounts of heat. The other statements are correct: Born-Haber cycle relation, bond enthalpy order (N≡N=946 kJ/mol > C≡N=891 > C≡C=619), and ice melting thermodynamics.

Multiple choice chemistry energetics and thermochemistry bond energies and enthalpy changes bond enthalpies enthalpies for different types of reactions

Which of the following relationships is not correct?

  1. $\Delta H = \Delta E + \Delta n _gRT$
  2. $\Delta H _{sub} = \Delta H _{fusion} + \Delta H _{vap}$
  3. $\Delta H _r^0 = \sum H _{f(reactants)}^0 - \sum H _{f(products)}^0$
  4. $\Delta H _r^0 = \sum B.E. $ of reactants $- \sum B.E. $ of products
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

From definition of Heat of Formation and Hess' law, $\Delta H _r^0 = \sum H _{f(products)}^0 - \sum H _{f(reactants)}^0$

Multiple choice physics types of energy renewable and non-renewable resources renewable and non-renewable sources of energy substances, objects and energy

What is the relationship between the kinetic energy($K$), potential energy($P$) and total energy($E$) of a system?

  1. $K=P+E$
  2. $E=P+K$
  3. $P=K+E$
  4. $E=PK$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Total mechanical energy of the system is equal to the sum of kinetic energy of the system and the potential energy of the system.

Thus, total mechanical energy  $E = K+P$

Multiple choice biology coal, petroleum and petrochemicals carbon cycling mineral coal carbon cycle coal and its products

Which of the following conditions regarding a chemical process ensures its spontaneity at all temperature ? 

  1. $\Delta A > 0, \Delta S < 0$
  2. $\Delta H < 0, \Delta S > 0$
  3. $\Delta H < 0, \Delta S < 0$
  4. $\Delta H > 0, \Delta S > 0$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

For a process to be spontaneous at all temperatures, the Gibbs free energy change (delta G = delta H - T*delta S) must be negative. This occurs when delta H is negative (exothermic) and delta S is positive (increase in entropy).

Multiple choice chemistry reactivity series and electrochemistry reactivity series and displacement reactions chemical properties of metals chemical properties of metals and non metals

Intensity of reaction of a metal with water depends upon its :

  1. mass number of metal

  2. chemical reactivity

  3. atomic no. of metal

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

Metals react with water to form a metal hydroxide or metal oxide and hydrogen gas. Intensity of reaction depends upon its chemical reactivity.

Multiple choice evs - i substances, objects and energy renewable resources alternative fuels and energy sources alternative sources of energy

Which one of the following is not a characteristic of a good fuel?

  1. No emission of smoke or harmful gases

  2. High ignition temperature

  3. High calorific value

  4. Not much ash(residue) after burning
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Characteristics of a good fuel are as follows:
1. Cheap and easily available.
2. Easy to store and transport.
3. Low ash content.
4. Should not produce any harmful substances.
5. High calorific value.
6. Moderate ignition temperature. 
Multiple choice botany ecosystem : structure and function energy flow in food chain food chain and energy flow energy flow in ecosystem

According to first law, energy cannot be created nor destroyed, but, can only show a state known as

  1. Utilized

  2. Thermodynamics

  3. Convection

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

The first law of thermodynamics states that energy is conserved; it can be converted from one form to another but cannot be created or destroyed. The process of changing energy from one form to another is called conversion.

Multiple choice botany ecosystem : structure and function energy flow in food chain food chain and energy flow energy flow in ecosystem

Choose the correct answers from the alternatives given .
Which of the following statements is not a consequence of the second law of thermodynamics?

  1. While the total amount of energy is unchanged, the energy lost as heat is no longer useful to the cell in doing work

  2. Reactions that occur spontaneously are those that increase the amount of useful energy in a system

  3. Amount of disorder in the universe is always increasing

  4. To maintain rganisation of a cell, a continual input of energy is required
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In spontaneous reactions release free energy and it moves to a lower, more thermodynamically stable energy state. Hence, instead of an increase in the amount of useful energy in a system spontaneous reactions release free energy. 

So, the correct option is 'Reactions that occur spontaneously are those that increase the amount of useful energy in a system'.

Multiple choice botany ecosystem : structure and function energy flow in food chain food chain and energy flow energy flow in ecosystem

Choose the correct answers from the alternatives given .
Which of the following best describes the second law of thermodynamics?

  1. Energy is neither created nor destroyed, but it can change from one energy form to another

  2. Energy can be created from matter or used to produce mailer

  3. Some useful energy is lost as heat whenever an energy transfer occurs

  4. Energy transfers are always 100% efficient in changing energy from one useful form to another
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The second law of thermodynamics states that whenever energy is transformed, there is a loss of energy through the release of heat. This occurs when energy is transferred between trophic levels as illustrated in a food web. When one animal feeds off another, there is a loss of heat (energy) in the process. Additional loss of energy occurs during respiration and movement. Hence, more and more energy is lost as one moves up through trophic levels.
So, the correct option is 'Some useful energy is lost as heat whenever an energy transfer occurs'.
Multiple choice botany ecosystem : structure and function energy flow in food chain food chain and energy flow energy flow in ecosystem

Choose the correct answers from the alternatives given .
According to the first law of thermodynamics

  1. systems rich in energy are intrinsically unstable

  2. all processes increase the entropy of the universe

  3. energy is conserved in all processes

  4. matter can be neither created nor destroyed
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The First Law of Thermodynamics states that heat is a form of energy, and thermodynamic processes are therefore subject to the principle of conservation of energy. This means that heat energy cannot be created or destroyed.

So, the correct option is 'energy is conserved in all processes'.