Multiple Choice
Which of the following solvents would you expect to dissolve aspirin?
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14. Solutions
Solutions: Solubility and Intermolecular Forces
Multiple Choice
According to Hess's law which of the following terms for the formation of a solution is always exothermic?
A
ΔHsoln
B
ΔHmix
C
ΔHsolute
D
ΔHsolvent
E
None of the enthalpies is always exothermic.
Verified step by step guidance1
Understand that Hess's Law states that the total enthalpy change for a reaction is the same, no matter how many steps the reaction is carried out in.
Recognize that the formation of a solution involves three main enthalpy changes: the enthalpy change for separating the solute molecules (ΔHsolute), the enthalpy change for separating the solvent molecules (ΔHsolvent), and the enthalpy change for mixing the solute and solvent (ΔHmix).
Recall that ΔHsolute and ΔHsolvent are typically endothermic because energy is required to overcome intermolecular forces.
Understand that ΔHmix is exothermic because energy is released when solute and solvent molecules interact and form new intermolecular forces.
Conclude that according to Hess's Law, ΔHmix is the term that is always exothermic in the formation of a solution.
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