• Support PF! Buy your school textbooks, materials and every day products Here!

Question about Q=mcΔT when doing calorimetry

  • Thread starter deezer
  • Start date
  • #1
18
0

Homework Statement



When using the equation Q=mcΔT for the substance being tested is it the mass of the substance or the mass of the substance + mass of water.

Homework Equations





The Attempt at a Solution



So when I solve calorimetry problems, I usually find Qwater. Then I set Qsubstance=-Qwater. But then I have to use mcΔT, I'm not sure if it's the mass of the substance or the mass of the substance + mass of the water because I've gotten a few questions wrong and the textbook briefly mentioned the sum of masses but gave no examples. Thanks for your input.
 

Answers and Replies

  • #2
688
1
Re-arrange your equation as follows:

c = [itex]\frac{Q}{mΔT}[/itex]

Since 'c' is for the substance, what would 'm' be for?
 
  • #3
18
0
m is for the substance right? Not the sum of the mass of the water and substance.
 
  • #4
688
1
m is for the substance right? Not the sum of the mass of the water and substance.
Yes, and you can relate to the definition of specific heat: energy required to raise the temperature of one unit mass of the 'substance' on unit degree.
 
  • #5
Borek
Mentor
28,358
2,746
Yes, and you can relate to the definition of specific heat: energy required to raise the temperature of one unit mass of the 'substance' on unit degree.
Like specific heat of brine :tongue:
 

Related Threads on Question about Q=mcΔT when doing calorimetry

  • Last Post
Replies
7
Views
7K
  • Last Post
Replies
0
Views
1K
Replies
8
Views
1K
Replies
5
Views
7K
Replies
1
Views
6K
  • Last Post
Replies
1
Views
2K
Replies
2
Views
14K
  • Last Post
Replies
2
Views
1K
  • Last Post
Replies
2
Views
1K
  • Last Post
Replies
16
Views
1K
Top