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Chemistry Homework Help => General Chemistry => Topic started by: kelly2429 on October 10, 2011, 02:25:30 AM

Title: specific heat capcity calculation. Regular Chem 30
Post by: kelly2429 on October 10, 2011, 02:25:30 AM
Given the following:  4 Al(s) + 3O2 (g) --> 2 Al2O3 (s)    ΔrxnH= -3202 kJ
    Determine the volume of water present in a calorimeter if 20.0 g of aluminum are burned in the reaction chamber, resulting in a increase of 15.7°C.

The answer given: Vwater= 9.02 L
Title: Re: specific heat capcity calculation. Regular Chem 30
Post by: uma on October 10, 2011, 03:22:46 AM
convert g of Al to moles of Al
now from the reactions 4 moles of Al ---> 3202KJ of energy
get the amount of energy for the calculated moles of Al
This amount is q
now q = m c delta t -----(1)
m = mass of water = kg  of water as density of water is 1Kg/L

now you have c of water = 4.18KJ /Kg .deg C
delta t = 15.7 deg C so plug in value of q , delta t and c  in eq 1 to m of water