Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Heat capcity of napthalene

  1. Jun 12, 2007 #1
    You burn 136.8 mg of naphthalene in a calorimeter and the temperature of the calorimeter rises by 3.29 oC. Determine the calorimeter heat capacity in J K-1. The molar mass of naphthalene is 128.18 g mol-1

    This is a question from a quiz I have to do.
    this is wat I did.
    Ccal=delta H/delta n=0.1368g/128.18g/mol
    =1.06E-3moles

    I dont know how to calc delta H from this info but I looked it up on the net and found 72.6+0.6kJ/mol.
    Thats not right is it coz when I put this information in the formula
    Ccal=((72.6+0.6)x1000j/molx1.06E-3)/(3.29+273.15)

    I got it wrong... any help???
    Does anyone know if my value for entropy of napthalene is right?
     
  2. jcsd
  3. Jun 12, 2007 #2
    heat of combustion of naphthelene=5156 kJ/mole. I think u may equate this to heat gained by calorimeter.
     
  4. Jun 12, 2007 #3
    Thanks I will try that!
     
  5. Jun 12, 2007 #4
    Yeah I just tried to use that and still got it wrong its so frustrating! I will go and see my lecturer now and hopefully he can help. Can u see anything wrong with my process?
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook