Question

Consider a reaction that connects the ends of a chain of carbons to form a ring. The closure of the ring results in the formation of a new chemical bond, with the bonding electrons going into a bonding sigma molecular orbital at a lower energy. Which of the following statements correctly describes the resulting enthalpy, entropy, and heat changes? Mark all that are correct.

A. The entropy of the surroundings decreases (AS surr < 0) because the closure of the ring results in fewer conformations for the system.
B. The system releases energy to the environment, because its internal energy decreases.
C. The entropy of the surroundings increases (AS surr > 0) because the surroundings absorb heat released by the reaction, and become more disordered.
D. The entropy of the system decreases (AS sys < 0) because the closure of the ring reduces the number of conformations the ring can adopt.
E. The enthalpy or internal energy of the system decreases (AH sys < 0) because the electrons that form the bond enter an orbital that is at a lower energy.

Answer 1

The system releases energy to the environment, because its internal energy decreases.

The entropy of the surroundings increases (AS surr > 0) because the surroundings absorb heat released by the reaction, and become more disordered.

The entropy of the system decreases (AS sys < 0) because the closure of the ring reduces the number of conformations the ring can adopt.

The enthalpy or internal energy of the system decreases (AH sys < 0) because the electrons that form the bond enter an orbital that is at a lower energy.

Step-by-step explanation:

Now we know that when a reaction is exothermic heat is given off. In this case, we have a reaction that connects the ends of a chain of carbons to form a ring. The bonding electrons now move into a lower energy bonding sigma molecular orbital.

This leads to a decrease in the entropy and enthalpy of the system because energy is given off, the closure of the ring reduces the number of conformations the ring can adopt and the electrons that form the bond enter an orbital that is at a lower energy.

The entropy of the surroundings is increased as energy is given out. The surroundings absorb heat released by the reaction, and become more disordered.