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Taryn
Jun12-07, 07:27 AM
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?

Amith2006
Jun12-07, 04:21 PM
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?

heat of combustion of naphthelene=5156 kJ/mole. I think u may equate this to heat gained by calorimeter.

Taryn
Jun12-07, 08:02 PM
Thanks I will try that!

Taryn
Jun12-07, 08:08 PM
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?