Question

identify the following processes as spontaneous or nonspontaneous, and explain your choice.

a. A photovoltaic cell in a solar panel produces electricity.

b. Helium gas escapes from a latex party balloon.
c. A sample of pitchblende (uranium ore) emits alpha particles.

Answer 1

Spontaneous processes are those in which a system looses its free energy and goes to a more stable lower energy state. If the system is isolated and we do not have energy excahnge with surroundings then we deccide its spontaneity based on cahnge in entropy.

a. A photovoltaic cell in a solar panel produces electricity by absorbing solar energy. Its energy content increases. Hence it is a non spontaneous process.

​b. During the escape of the He gas from a latex balloon though there is no temperature change, the entropy of the gas increases and hence it is a spontaneous process.

c. Radioactivity is a spontaneous process because here a unstable higher energy nucleus looses energy to reach a stable lower energy state.