A 210 g iron bar is heated and then placed in 100. g of water in an insulated container. The water temperature increases from 21.2 °C to 53.3 °C. What was the initial temperature of the iron bar?

Question

(Specific heats: cFe = 0.449 J/gK; cwater = 4.184 J/gK)

Answer 1

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

Answer 2

How much energy is required to heat 120.0g of water from 2.0°c to 24.0°c (Cp of H2O=4.184J/g