Homework Help: Help finding specific heat of metal in calorimeter

1. Jan 27, 2010

kriegera

1. The problem statement, all variables and given/known data
A piece of metal of weight 50 grams is heated to a temperature of 100°C and then introduced into a calorimeter containing water at 14°C, the maximum temperature reached being 20°C. If the weight of the calorimeter is 5 grams, the specific heat of the metal of which it is made is 0.095 and the weight of the water it contains is 92 grams, calculate the specific heat of the given metal.

2. Relevant equations
ΔH=cmΔT
C=H/mΔT

3. The attempt at a solution

I thought I had this figured out but I'm stuck on two points: This is what I have:
Because the heat of the reaction is absorbed by the water, causing it to warm up, we will use the mass of the water vs. the mass of calorimeter. This is the substance where the reaction/energy/H is taking place.
ΔH=(4.189)(92)(20-14) = 2,312.328 J

Now we use this information to find the specific heat of the given metal:
C=H/mΔT = 2,312/(50)(100) = .46 J/g.K

But I'm confused on whether
A) Do I use the mass of the calorimeter mass or the mass of water for the first equation
B) What is the change in the temperature of the given metal? Do I stick with 100 b/c it doesn’t say or do I use 100-20C?

2. Jan 27, 2010

rl.bhat

A) The first equation should be
(Mc*cc + Mw*cw)(T1-T2)
B) You are right.

3. Jan 27, 2010

kriegera

can you label equation A? i can't figure out the components.

4. Jan 27, 2010

rl.bhat

(mass of the calorimeter* specific heat of the calorimeter + mass of the water*specific heat of the water)*Fall in the temperature.

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