# 25.000 grams of water at 45.00oC was added to 25.00 grams of water at 20.30oC in a coffee cup calorimeter.

25.000 grams of water at 45.00oC was added to 25.00 grams of water at 20.30oC in a coffee cup calorimeter. Upon mixing, the equilibrium temperature attained by the system was 31.40oC. The specific heat of water is 4.184 J/goC. What is the calorimeter constant Ccal in J/oC for the coffee cup calorimeter?

Choice:

23.56
232.8
47.14
465.1

a. 2.503 g of ammonium chloride NH4Cl are added to a calorimeter cup containing 25.30 g of water at 22.0oC. The temperature of the calorimeter decreases to 17.3oC. Assume the specific heat of solution is 4.184 J/goC. Assume the calorimeter constant you determined in question 1. Is this process endothermic or exothermic?

b. Assume the calorimeter constant you determined in question 1. Is this process endothermic or exothermic? How many moles of ammonium chloride are in the solution?

c. Assume the specific heat of solution is 4.184 J/goC. Assume the calorimeter constant you determined in question 1. Determine the molar enthalpy of dissolution ΔHdissolution of NH4Cl in kJ/mol.