Hot water is added to three times its mass of water at 10oC and the resultant temperature is 20oC. What is the initial temperature of the hot water?

Hot water is added to three times its mass of water at 10oC and the resultant temperature is 20oC. What is the initial temperature of the hot water?

Answer Details

Heat loss = heat gained

mh x ch x $\theta$h = mc x cc x $\theta$c

mh x ch x ($\theta$ - 20) = mc x cc x (20 - 10)

ch = cc ; mc = 3mh

therefore, $\theta$ = 50oC