Question

which of these factors will cause a solid solute to dissolve faster?
○ increasing the air temperature
○ increasing the amount of solute
○ increasing the amount of solvent
○ increasing the surface area of solute

Explanation:

• For "increasing the air temperature": Dissolution of a solid solute in a liquid solvent is mainly affected by the temperature of the solvent (liquid), not air temperature. So this does not speed up solid solute dissolution.
• For "increasing the amount of solute": Increasing the amount of solute does not make it dissolve faster; it may even lead to saturation faster, but does not affect the rate of dissolution of the solute that is in contact with the solvent.
• For "increasing the amount of solvent": Increasing the amount of solvent affects the total amount of solute that can be dissolved (solubility limit) but not the rate at which the solid solute dissolves.
• For "increasing the surface area of solute": When the surface area of the solid solute is increased (e.g., by crushing it into smaller pieces or powder), more of the solute's surface is exposed to the solvent. This allows more solvent molecules to interact with the solute particles at the same time, thus increasing the rate of dissolution.

Answer:

D. increasing the surface area of solute