Science Buddies: "Ask an Expert"

Hi. Can you please solve these questions
A:
1) aspirin was synthesized from salicylic acid and ethanoic anhydride. Why was sulphuric acid added in the reaction mixture?
2) In this experiment aspirin was synthesized from salicylic acid and ethanoic anhydride. Why was sulphuric acid added in the reaction mixture?
3) Why was recrystallization of aspirin performed? What makes a good recrystallization solvent and why?

T:
1) Given the formula mass of MgCl2 is 95.21 g mol-1, how many grams of magnesium chloride salt was provided to make up 0.01 mol supplied in your experiment?
2) Draw both an ammonium ion and a free chloride ion in water. Next decide whether the solvated ammonium ion and chloride ion are cations or anions.
3) The overall heat of solution for a solid dissolving in a liquid is equal to the heat of solvation minus the crystal lattice energy (the energy that binds oppositely-charged cations and anions together in a crystal). Both processes are exothermic for ionic compounds dissolving in water.
Overall: ΔHsoln = (heat of solvation) – (crystal lattice energy)
- Which term is therefore responsible for making the process of salt dissolution in water either exothermic or endothermic overall?
- What is the heat of solvation called when the solvent is water?


Thanks in advance

Hi - Experts in the forums can not help with homework questions. You will need to consult your class materials, notes, or other resources to complete your work.

Amy
Science Buddies