When heat is added to a system at constant temperature, which of the following is possible.

Heat added to a system is equal to

When a catalyst is added to a system the:

When heat is added to a system, which of the following is not possible ?

Heat is added to a substance, but its temperature does not rise. Which one of the following statements provides the best explanation for this observation ?

When thermodynamic system returns to its original state, which of the following is NOT possible?