Polar protic solvents actually speed up the rate of the unimolecular substitution reaction because the large dipole moment of the solvent helps to stabilize the transition state. The highly positive and highly negative parts interact with the substrate to lower the energy of the transition state.
It doesn't because pepper does not dissolve
Thermal energy is defined as the total kinetic energy of all particles in an object. Even though the cup of water has a higher temperature, the bathtub has more thermal energy because it contains much more mass of water compared to the cup.