1. The problem statement, all variables and given/known data How much Fe at 200.0C must be placed in 100.00g of water at 20C so that the temperature of both will be at 35.0? 2. Relevant equations Q=MCdeltaT 3. The attempt at a solution Energy required to raise water is 6300 J So I did by: (keep in mind I used sig figs) Q=100.00(4.18)15 Q=6300 And then.. I assumed I must plug in 6300 as a negative to the FE to get the amount needed I did -6300=x(.449)165 x=-6300/74.1 x=85g I go to check my work by doing taking out the final temp and trying to solve for it by using the grams I did so by: (85).449(Tf-200.0)=(100.0)4.18(35.0-Tf) 38Tf-7600=14600-418Tf 456Tf=22200 And got 48.7 Which is not so close to 35C Am I checking this wrong or am I doing the problem wrong?