Did TBR use heat capacity when they meant specific heat?

[Meredith92]

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Example 8.18 in gen chem book 2 of TBR says "What is the heat capacity of a material that requires 3.0 kcal to increase a 15.0 g sample from 25 degrees C to 75 degrees C
They used q=mC deltaA and plugged in 3000cal=15g (C) (50K) so C=3000cal/(15g)(50K)=3000cal/750gK

so C is 4 cal/gK

However I thought (based on another thread i found) that specific heat is cal/gK whereas heat capacity is cal/K

Which one is correct? I just want to make sure I dont use the wrong one on thursday! Thanks!

 

[milski]

You are right. Specific heat capacity is per unit mass and heat capacity is property of the whole object/system.

When some sloppiness is ok, people might skip 'specific,' if it is obvious from the context. I would hope that the exam will not make you deal with such ambiguities.

 

[Meredith92]

Thanks! It's a little surprising tbr wasn't being specific, but oh well thanks for your help!

 

[milski]

It happens, I also misuse speed vs. velocity occasionally. 🙂 Most of the time you deal with specific heat capacity anyway - you'd have to measure it for each object separately otherwise.

PS: and you earn 1 bonus point for the "specific" pun.

 

[Meredith92]

haha thanks🙂 i try, i try

 

[BerkReviewTeach]

Thanks! It's a little surprising tbr wasn't being specific, but oh well thanks for your help!

There are a few of these in the book that they know about. There's another one with density and specific gravity. I think they leave one here and there because the AAMC sample materials also have one here and there. I don't think it will make any difference on your MCAT, but it's good to see that you are paying attention. Keep the energy and good feelings up for a few more days! Best of luck on Thursday!!!