November 01, 2024, 12:27:41 PM
Forum Rules: Read This Before Posting


Topic: Enthalpy of fusion/molar heat capacity question please help  (Read 5923 times)

0 Members and 1 Guest are viewing this topic.

Offline lbk

  • Very New Member
  • *
  • Posts: 1
  • Mole Snacks: +0/-0
Enthalpy of fusion/molar heat capacity question please help
« on: November 04, 2006, 09:34:22 PM »
I really need help on this question.  I can't just do the M1C1DT = M2C2DT equation, because I don't know how the enthalpy of fusion fits in.  The answer in the back of the book is 10.4 degrees celsius but I don't know how to get there.  Thanks in advance for your *delete me*

Suppose an ice cube weighing 36.0g at a temperature of -10.0 degrees celsius is placed in 360 g of water at a temperature of 20 degrees celsius.  Calculate the temperature after thermal equilibrium is reached, assuming no heat loss to the surroundings.  The enthalpy of fusion of ice is (DHfus)   6.007 kJ/mol.  The molar heat capacity (cp) of ice is 38 J K- mol- and cp of water is 75 J K- mol-

Offline enahs

  • 16-92-15-68 32-7-53-92-16
  • Retired Staff
  • Sr. Member
  • *
  • Posts: 2179
  • Mole Snacks: +206/-44
  • Gender: Male
Re: Enthalpy of fusion/molar heat capacity question please help
« Reply #1 on: November 04, 2006, 11:58:13 PM »
I actually get 10.9, using the numbers provided.

You are just using q1+q1+q3...=0 (where typically you just have two terms, and you can do this because you are assuming no heat is lost).

m1*Cp1*(x-Ti)1 + m2*Cp2*(x-Ti)2 + m*DHfus = 0
Solve for x.

Sponsored Links