# AAMC 5R - heat capacity = specific heat?

Discussion in 'MCAT: Medical College Admissions Test' started by Dr. Gigglez, Aug 12, 2006.

1. ### Dr. Gigglez Member 2+ Year Member

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hey guys,

i just want to double check: heat capacity = the specific heat X the mass right?

anybody else notice this problem from the 5R? (PS question 48)

2. ### kaml20 Member Physician 10+ Year Member

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wheres change in temperature?

3. ### kaml20 Member Physician 10+ Year Member

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heat = heat capacity * mass * temp change

make sure you have 4*10^-3

4. ### Foolins Member 2+ Year Member

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you're right. The "specific" in specific heat capacity just means per unit of mass. So heat capacity is multiplied by the mass. I hope it's all in grams.

5. OP

### Dr. Gigglez Member 2+ Year Member

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hey kaml20,

thanks for the quick response, but what i meant is that since they give you the heat capacity, why do you have to multiply by the mass again, since isn't the definition of heat capacity, the specific heat X mass? (or am i mistaken?)

heat = specific heat * mass * temp change

is the same as

heat = heat capacity * temp change?

does the heat capacity just equal the specific heat?
or does it equal the specific heat X mass?

6. OP

### Dr. Gigglez Member 2+ Year Member

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if you look at 5R/PS/48, they treat the heat capacity as the specific heat - is this an AAMC mistake?

7. ### kaml20 Member Physician 10+ Year Member

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i see what your saying now, and now im confused lol
its probably mislabled but the units arent which is wierd.

8. ### estairella Senior Member 10+ Year Member

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It's an incorrect label, but I don't think you REALLY need to know the difference between heat capacity and specific heat (capacity), other than how to use them (and that one is extensive, while the other is intensive).

In this case, solve by looking at the units (its units clearly show that it is the specific heat... and if you tried solving without mass, you wouldn't get any of those answers), instead of with your memorized equations (which, btw, are correct).

9. OP

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thanks guys!

10. ### Knickerbocker 2+ Year Member

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When I came across that problem, I couldn't remember the exact way to work it. But here's a tip that works for a lot of problems. Pay very close attention to the units of both what the answer should be and the values you have to work with. A lot of times all you need is a little dimensional analysis to solve the problem.

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