25200 J of heat are added to 2.0 kg of mercury to reach a final temperature of 130°C. What was the initial temperature (°C) of the mercury? (NOTE: The specific heat capacity of mercury is 0.14 J/g°C)

Question

25200 J of heat are added to 2.0 kg of mercury to reach a final temperature of 130°C. What was the initial temperature (°C) of the mercury? (NOTE: The specific heat capacity of mercury is 0.14 J/g°C)

Answer 1

Once again, you can use q = mC∆T (just be careful to use correct units of g or kg)

q = heat = 25,200 J

m = mass = 2.0 kg = 2000 g

C = specific heat = 0.14 J/gºC

∆T = change in temperature = ?

25,200 J = (2000 g)(0.14 J/gºC)(∆T)

∆T = 25,200 J/(200g)(0.14 J/gºC)

∆T = 90ºC

Since the final temperature is 130ºC the initial temperature must have been 130º - 90º = 40ºC initial temp.