A 100.0 g sample of water at 27.0°C is poured into a 77.4 g sample of water at 89.0°C. What will be the final temperature of the water?

Answer 1

heat gained by cool H2O + heat lost by warm H2O = 0
[mass cool H2O x specific heat H2O x (Tfinal-Tinitial)[ + [mass warm H2O x specific heat H2O x (Tfinal-Tinitial)] = 0
Substitute and solve for Tf.

Answer 2

M= 100.0-g
C=2.06J/gC
Ti=116
Tf=75.0