Beverage companies use the principles of calorimetry and heat exchange to market

Question

Beverage companies use the principles of calorimetry and heat exchange to market new self-heating coffee drinks. These containers consist of a dual chamber where the beverage is in the internal chamber and the reaction used to heat the beverage is contained in the other. The following exothermic dissolution reaction is responsible for the heat exchange. CaCl2 (s) Ca2+ (aq) + 2 Cl- (aq) Hdissolution = -82.9 kJ/mol A) How much heat (in kJ) is liberated by dissolving 5.0 g CaCl2 in water? (2 pts)

B) Calculate the final temperature of the drink in the internal container if all of the heat generated from the dissolution is transferred. Assume that the mass of the drink is 15.0 g, its specific heat is 4.18 J/g °C, and the initial temperature is 25°C. (2 pts

Explanation / Answer

CaCl2 (s) Ca2+ (aq) + 2 Cl- (aq) Hdissolution = -82.9 kJ/mol

A) No of mol of CaCl2 = 5/110.98 = 0.045 mol

heat leberated = 0.045*82.9 = 3.7305 kj

B) q = m*s*DT

3.7305*10^3 = 15*4.18*(x-25)

x = final temperature = 84.5 C

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