Briefly explain why sublimation occurs.

Sublimation is basically cause by the heat absorption and this process is an endothermic since it require extra energy.

It basically provide sufficient energy to molecules to control the various type of attractive forces from the neighbors and then convert it into the vapor phase.

Sublimation occur when the particle of gases become cold because some substances has high vapor pressure. Sublimation is the endothermic change and it occur below the triple point in terms of pressure and temperature.

the correct answer is:

a. formation of precipitation

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.