chemistrythermochemistry
posted by james .
A student mixes 85.7 g of water at 68.0°C with 50.7 g of water at 24.5°C in an insulated flask. What is the final temperature of the combined water

call the 85 g water water1, and the other water2.
sum of heat changes =0
heatfromwater1+heatfromwater1=0
One will be negative, as one of them cools.
mass1*cw*deltaTemp1+mass2*cw+deltaTemp2=0
I assume you can handle it from here. Tf in each will be the same, ti for each is given. A little algebra in this...