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Hi! Can someone please explain to me how to go about problem #35?

-- Anonymous, February 06, 2000



Do not worry about signs while doing calorimeter problems. Then when you have found dH. Make sure it is negetive for an exothermic reaction (increase in temp), and postive for an endothermic reaction (decrease in temp).

heat lost by solution= heat gained by KBr= specific heat*mass*dT=1800J

mass = the total mass of the solution = 125g(water) + 10.5g(KBr)

That gives you the dH for 10.5g of KBr

To get dH in J/g = dH/mass of KBr = 170J/g

Then to get dH in J/mol = 170J/g * MW of KBr = 20000 J/mol

**Make sure the your answer is positive because the temp goes down.

-- Anonymous, February 06, 2000

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