# Thermodynamics question

1. Oct 25, 2009

### physicsman2

1. The problem statement, all variables and given/known data
A 100-g piece of metal initially at T = 75oC is submerged in 100 g of water initially at T = 25oC. The specific heat capacity of iron is 0.45 J g-1 °C-1 and the specific heat capacity of water is 4.18 J g-1 °C-1. What is the final temperature of both substances in oC?

2. Relevant equations
q=mc(delta T)

3. The attempt at a solution
well i tried to set mc(delta T)=mc(delta T), plug in all the values and solve for T(final), but i keep getting the wrong answer

2. Oct 25, 2009

### rock.freak667

What numbers did you put for each of the changes in temperature?

3. Oct 25, 2009

### physicsman2

mc(delta T)=mc(delta T)

(100)(.45)(T(final)-75)=100(4.184)(T(final)-25)

i solved that for T(final) but still got the wrong answer

4. Oct 25, 2009

### rock.freak667

For the term on the left side, (the metal at 75), it can't gain heat, it only loses heat. So That should be (75-Tfinal). Understand?

5. Oct 25, 2009

### physicsman2

oh, now i understand, thank you so much