Specific Heat Capacity of a brass cylinder

  • Thread starter greenfloss
  • Start date
  • #1
11
0

Homework Statement



The temperature of a brass cylinder of mass 100g was raised to 100 degree celsius and then transferred to a thin aluminium can of negligible heat capacity. The aluminium can contained 150g of paraffin at 11 degree celcius. If the final steady temperature after stirring was 20 degree celsius, claculate the specific heat capacity of paraffin

(Neglect heat losses, and assume specific heat capacity of brass= 38 J/gK

Homework Equations



Specific heat capacity * mass * change in temperature = Energy lost/gained

The Attempt at a Solution



The answer given by my teacher is: 2250J/Kg.K

My answer and workings:


100 * 28 * 80 = 150 * 9 * Specific heat capacity of paraffin

Specific Heat Capacity = 225 J/g.K

Even if I change this value to J/kg.K (which I don't know how to), I won't get the answer my teacher gave- that much I can tell :-(

Someone I asked gave the correct answer, but they didn't take the weight of the cylinder into account. Why is this possible?
 
Last edited:

Answers and Replies

  • #2
hage567
Homework Helper
1,509
2
Based on the numbers in your question, I get the same answer as you. I think problem is with the specific heat capacity of brass. I think it should be 0.38 J/gK (I looked it up). Using that value will give you the same answer as your teacher if you convert it to J/kgK. Are you sure you copied it down right?


Someone I asked gave the correct answer, but they didn't take the weight of the cylinder into account. Why is this possible?


Well, I can't see how they got the right answer by doing that, why would they leave out the mass of the cylinder only? Did they still include the mass of the paraffin? I think it might just be coincidence that it came out to the right answer. But I don't think the units would match that of your teacher's answer (so technically it would be wrong). I'm just guessing since I don't know what they really did.
 
  • #3
11
0
Thank you sooo much! So my method is right then. That's all I wanted to know. :-D
 

Related Threads on Specific Heat Capacity of a brass cylinder

  • Last Post
Replies
9
Views
12K
Replies
2
Views
5K
  • Last Post
Replies
2
Views
15K
  • Last Post
Replies
2
Views
3K
Replies
3
Views
9K
  • Last Post
Replies
6
Views
3K
  • Last Post
Replies
7
Views
825
  • Last Post
Replies
12
Views
3K
Replies
8
Views
4K
  • Last Post
Replies
3
Views
665
Top