Question

It takes 1 minute for a certain amount of potassium bromide (KBr) to dissolve in 100 grams of water at 25 °C.

Which of the following will most likely happen if the same sample of potassium bromide is dissolved in 100 grams of water at 100 °C?

a) The sample will dissolve in exactly 1 minute.

b) The sample will dissolve in less than 1 minute.

c) The collision between particles of the sample will decrease.

d) The collision between particles of the sample will remain constant.

Answer 1

b) The sample will dissolve in less than 1 minute.

As the temperature increases, the kinetic energy of the particles in the solvent also increases, leading to increased frequency and energy of collisions between the solute particles and the solvent molecules. This results in faster dissolution of the solute in the solvent. Therefore, the sample of potassium bromide will dissolve faster in 100 grams of water at 100 °C compared to at 25 °C.