Question

Thermodynamics is not concerned with

• A. The energy changes involved in a chemical reaction
• B. The extent to which a chemical reaction proceeds.
• C. The rate at which the reaction proceeds
• D. The feasibility of a chemical reaction.

Answer 1

The correct option is C

The rate at which the reaction proceeds

Thermodynamics:

1. It is a discipline of physics that studies heat, work, and temperature, as well as their relationships with energy, radiation, and matter's physical properties.
2. It describes the feasibility of a chemical reaction as well as the energy changes related to a chemical reaction.

Explanation for the correct option:

In the case of option C,

1. Thermodynamics is concerned with the chemical changes of reaction, the feasibility of reaction, and the extent of reaction.
2. The Reaction Rate is the rate at which the reactants' or products' concentrations change per unit time in a chemical reaction.
3. $\mathrm{Rate}=\frac{∆\mathrm{Concentration}}{∆\mathrm{Time}}$
4. Thermodynamics is not concerned with the rate at which reaction proceeds.
5. The rate of reaction is constant or the reaction is in chemical equilibrium, during the thermodynamic processes.
6. It is dealt with in the kinetics of chemical reactions.

Hence, option (C) is correct.

Explanation for the incorrect option:

In the case of option A,

1. The difference in the amounts of stored chemical energy between the products and the reactants causes the energy change in a chemical reaction.
2. The chemical change in a reaction affects the internal energy of a system.
3. The chemical change in a reaction affects the thermodynamics of a system.
4. Hence, option A is incorrect.

In the case of option B,

1. The extent of a reaction is a quantity that indicates how far the reaction has progressed.
2. To a different extent, the thermodynamic properties of the system keep on changing.
3. So, the extent of reaction affects thermodynamics.
4. Hence, option B is incorrect.

In the case of option D,

1. For a reaction to be feasible at a given temperature, it must occur spontaneously, which means that no additional energy is required.
2. The feasibility of a chemical reaction depends on the sign of change in Gibbs free energy.
3. Gibbs free energy is a thermodynamic potential so the feasibility of a chemical reaction has an effect on thermodynamics.
4. Hence, option D is incorrect.

Hence, the option (A), (B), and (D) are incorrect.