Question

Identify two common observations indicating some solids, such as dry ice and mothballs have vapour pressures sufficient to sublime.

Short answer

Two common observations indicating that some solids, such as dry ice and mothballs have vapour pressures sufficient to sublimeare:

a) When temperature is below freezing point or

b) By detecting the aroma that is generated because of sublimation.

Step-by-step solution

Definition of evaporation

Evaporation is a natural process that occurs when a liquid transforms into a gaseous state, generating a pressure or temperature increase.

Identify the two common observations

One of the observations is disappearance of a solid ice even when the temperature is below freezing point. Another way is by detecting the aroma generated due to sublimation.

Hence, we can say that solids, such as dry ice and mothballs, have vapor pressures sufficient to sublime.