For a single substance at atmospheric pressure, classify the following as describing a spontaneous process, a nonspontaneous process, or an equilibrium system. a. Solid melting below its melting point
b. Gas condensing below its condensation point
c. Liquid vaporizing above its boiling point
d. Liquid freezing below its freezing point
e. Liquid freezing above its freezing point
f. Solid melting above its melting point
g. Liquid and gas together at boiling point with no net condensation or vaporization
h. Gas condensing above its condensation point
i. Solid and liquid together at the melting point with no net freezing or melting

Answer and Explanation:

a. Solid melting below its melting point  ⇒ Nonspontaneous

The process is spontaneous above the melting point.

b. Gas condensing below its condensation point  ⇒ Spontaneous

Below the condensation point, the subtance is liquid (it condenses)

c. Liquid vaporizing above its boiling point  ⇒ Spontaneous

A liquid vaporizes at a temperature above the boiling point, it passes from liquido to the gas state

d. Liquid freezing below its freezing point  ⇒ Spontaneous

A liquid freezes at a temperature below its freezeing point, it passes from the liquid to the solid state.

e. Liquid freezing above its freezing point  ⇒ Nonspontaneous

The freezing is spontaneous below the freezing point.

f. Solid melting above its melting point  ⇒ Spontaneous

A solid melts at a temperature above the melting point

g. Liquid and gas together at boiling point with no net condensation or vaporization  ⇒ Equilibrium system

The systems is at equilibrium: there is no net change toward the liquid or towards the gas state.

h. Gas condensing above its condensation point  ⇒ Nonspontaneous

The condensation is spontaneous at a temperature below the condensation point.

i. Solid and liquid together at the melting point with no net freezing or melting ⇒ Equilibrium system

The system is at equilibrium: there is no net change towards the solid or the liquid state.