Question

In a constant-pressure calorimetry experiment, a reaction gives off 22.8 kJ of heat. The calorimeter contains 150 g of water, initially at 20.4°C. What is the final temperature of the water? The heat capacity of the calorimeter is negligibly small.

Answer 1

Answer:

The final temperature of water is 56,7 ºC

Explanation:

We need to apply the specific heat capacity formula to solve this.

Q = m . C . ΔT

22,8 kJ =  150 g . 4,186 J/g °C . (Tfinal - 20,4º C)

(We need to convert kJ in J to use the specific heat of water, be careful with units)

22,8 kJ = 22800 J (x1000)

22800 J  =  150 g . 4,186 J/g °C . (Tfinal - 20,4º C)

22800 J = 627,9 J/ºC (Tfinal - 20,4º C)

22800 J / 627,9 ºC/ J = (Tfinal - 20,4º C)

36,3ºC = Tfinal - 20,4º C

36,3ºC + 20,4º C = 56,7 ºC