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

Answer 1

Which will make a solid solute dissolve faster?

- Increasing the temperature (of the solvent) — yes. Higher temperature raises molecular motion and collision rate, so solute dissolves faster.
- Increasing the amount of solvent — yes. More solvent lowers the solution concentration (driving force for dissolution) so dissolution proceeds faster.
- Increasing the surface area of the solute — yes. Smaller pieces expose more area to the solvent, increasing the rate.
- Increasing the amount of solute — no. Adding more solute does not speed up how fast each bit dissolves and can slow/stop dissolution by bringing the solution closer to saturation.

(“Air temperature” only helps if it raises the solvent’s temperature.)