Final answer:
The magnitudes of kf and kb depend on the identity of the solute and solvent, as well as the temperature. the values of kf and kb are also influenced by the temperature of the solution.
Step-by-step explanation:
The subject that affects the magnitudes of kf and kb is the solute and solvent. The values of kf and kb, which are the freezing point depression constant and boiling point elevation constant, respectively, depend on the chemical identity of both the solute and solvent.
For example, different solvents will have different values of kf and kb. Additionally, the values of kf and kb are also influenced by the temperature of the solution.