A coffee cup calorimeter was used to measure the heat of solution-the change in

Question

A coffee cup calorimeter was used to measure the heat of solution-the change in enthalpy that occurs when a solid dissolves in water. A 10.0 g sample of an ionic compound with a molar mass of 125.0 g/mol was added to a sample of deionized water to produce 60.0 grams of solution, After stirring and dissolving the solid, the temperature was found to change from 25.00 °C to 23.76 °C. Calculate the enthalpy of solution, AHsolution. per mole of salt dissolved. Assume the specific heat of the solution is 4.10 J/(g·°C) and the heat capacity of the calorimeter is 3.20 Jrc. Number Calculate the heat change experienced by the calorimeter contents, qcontents Number Calculate the heat change experienced by the calorimeter, cal Calculate the heat change produced by the solution process, qsol Number Calculate AHsolution, the enthalpy of solution for one mole of solid in kJ/mol. Number k.J/mol Previous Check Answ

Explanation / Answer

mass of ionic sample= 10 gm, molar mass= 120 g/mole, moles of ionic compound= 10/120 =0.0833

since the temperature drops down, the dissolution is endothermic.

the heat absorbed is taken by Calorimeter as well as the solution.

Heat removed from the solution= mass of solution* specific heat of solution* change in temperature =(10+60)*4.184*(25-23.76)=363 joules

heat change of calorimeter= Calorimeter constant* change in temperature =3.2*(25-23.76) = 4 joules

total heat absorbed= 363+4=367 joules

enthalpy change= heat absorbed/moles= 367/0.0833=4406 joules/mole=4.406 Kj/mole

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