The dissolving process is exothermic when the energy

a) released in solvation exceeds the energy used in breaking up solute-solute and solvent-solvent interactions.

b) used in solvation exceeds the energy released in breaking up solute-solute and solvent-solvent interactions.

c) released in solvation is about the same as the energy used in breaking up solute-solute and solvent-solvent interactions.

d) used in solvation is less than the energy released in breaking up solute-solute and solvent-solvent interactions.

e) used in solvation is about the same as the energy released in breaking up solute-solute and solvent-solvent interactions.

A

Explanation:

The dissolving process depends on the interaction between solute and solvent (solvation) and the breaking up of the intermolecular bond between solutes. The former is exothermic in nature, while the later is endothermic. Energy is released when solute-solvent particles interact. When this energy exceeds the energy required to break intermolecular bonds between the solute particles, dissolution is exothermic.

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%