Question

Which of the following statements correctly reflect the relationship between the spontaneity of a reaction and the sign of Δh? Select all that apply.

1) An endothermic process may be spontaneous under one set of conditions but nonspontaneous at a different temperature and pressure.
2) It is possible for an exothermic process to be nonspontaneous.
3) The spontaneity of a process is easily determined from the sign of Δh for the reaction.
4) An exothermic process is always spontaneous.

Answer 1

An endothermic process may be spontaneous under one set of conditions but nonspontaneous at a different temperature and pressure. It is possible for an exothermic process to be nonspontaneous.

Step-by-step explanation:

The correct statements that reflect the relationship between the spontaneity of a reaction and the sign of Δh are:

1. An endothermic process may be spontaneous under one set of conditions but nonspontaneous at a different temperature and pressure. For example, ice melting at temperatures above 0°C.
2. It is possible for an exothermic process to be nonspontaneous. Not all exothermic reactions are spontaneous, as there are other factors like entropy that need to be considered.

It is important to note that the spontaneity of a process cannot be easily determined solely by the sign of Δh. There are other factors, such as entropy changes and temperature, that also play a role in determining spontaneity.