Question

150mL of water at 25oC is mixed 325mL of 80oC water in a sealed vacuum insulated vessel. Determine the final temp of the combined 475mL of water. The density of water is 1g/mL. What's the final temperature??

Answer 1

density of water = 1g/ml

so, mass of water at 25°C =150g

and mass of water at 80°C = 325g

Let time of mixture is T.

heat lost by 325g water = heat gained by 150g water

[ heat = ms∆T, where m is mass , s is specific heat capacity and ∆T is change in temperature]

or, 325 × s × (80 - T) = 150 × s × (T - 25)

or, 13 × (80 - T) = 6 × (T - 25)

or, 1040 - 13T = 6T - 150

or,1040 + 150 = 13T + 6T

or, 1190 = 19T => T = 62.63°C

hence, answer is 62.63°C