# chemistry

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Using a coffee-cup calorimeter, it is found that when an ice cube with a mass of 24.6 g melts, 8.19 kJ of heat are absorbed.
(a) Calculate the change in enthalpy per gram and per mole of water.

(b) Write the thermochemical equation for this physical change.
(c) What mass of ice must be melted to produce 10.0 kJ of heat?

• chemistry -

delta H = 8190 J/24.6 g
Multiply by molar mass water to convert to J/mol.

H2O(s) + heat ==> H2O(l)

I have a problem with the last question. If ice is to be melted, it must absorb heat, not produce heat. The number you want is J/g (from #1) x #grams = 10,000. Solve for #grams.

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