An aluminum calorimeter has a mass of 60g and an initial temperature of 25oC. What is the final temperature attained when 86.8g of water at 90oC is poured into it?

Answer 1

The sum of the heats gained is zero.
heatgainedwater+heatgainedAl=0
86.8*cwater*( Tf-90 )+60*calum*(Tf-25)=0

Answer 2

Ok, but then how do you find Tf?