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Another specific heat question

  • Thread starter dav1d
  • Start date
  • #1
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Homework Statement



A 28.2 g sample of nickel is heated to 100 degrees C and placed in a coffee cup calorimeter containing 150g of water at a temperature of 13.5 degrees C. After the metal cools, the final temperature of the metal and water is 25 degrees C. Calculate the specific heat capacity of nickel.


Homework Equations



Q=mcdeltaT

The Attempt at a Solution



first calculate Q for water.
Q=mcT
=(150g)

But what is c for water at 13.5degrees??? Problem, now I don't know what to do from here.
 

Answers and Replies

  • #2
195
0
c = the specific heat capacity which is a constant or a material ie. the specific heat capacity for water is 4.18 JK^-1g^-1


;)
 
  • #3
65
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  • #4
195
0
Um, water has different c values at different temperatures.

http://en.wikipedia.org/wiki/Heat_capacity#Table_of_specific_heat_capacities

Water at 100 °C (steam) gas 2.080 37.47 28.03
Water at 25 °C liquid 4.1813 75.327 74.53 4.1796
Water at 100 °C liquid 4.1813 75.327 74.53 4.2160
Water at −10 °C (ice)[20] solid 2.11 38.09 1.938
not according to my text book. I think that specific heat capacitys must change when they states are change. If that is that case, at 13 degrees, water should still be 4.1813. (I'm only making assumptions here)
 
  • #5
Borek
Mentor
28,353
2,742
As explained in other thread - specific heat is a function of temperature, but differences are usually small enough that we can assume it is constant - as long as the substance doesn't change its state. This is especially true for water and most metals between 0-100°C. Use 4.18 J/Kg and don't worry.
 
  • #6
65
0
Sorry. Will fix later.
 

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