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# Enthalpy change of solution watch

1. How can I calculate the enthalpy change of solution from heat energy absorbed in a reaction ... E.g. "2.42g of potassium chloride are dissolved in 44.96g of water. The temperature of the water falls from 22.6 to 19.9(degrees celcius). A) calculate heat energy absorbed in this reaction = 507.4
B) hence calculate the enthalpy change of solution for potassium chloride in KJmol^-1 ?
2. (Original post by Hardy jacks)
How can I calculate the enthalpy change of solution from heat energy absorbed in a reaction ... E.g. "2.42g of potassium chloride are dissolved in 44.96g of water. The temperature of the water falls from 22.6 to 19.9(degrees celcius). A) calculate heat energy absorbed in this reaction = 507.4
B) hence calculate the enthalpy change of solution for potassium chloride in KJmol^-1 ?
Energy change is given by E = mcΔT
Then divide by the number of moles of solute used to give energy change per mol.
3. is the answer -15.6 kg mol-1?
4. (Original post by coconut64)
is the answer -15.6 kg mol-1?
No, it's +15.6 kJ mol-1
5. (Original post by charco)
No, it's +15.6 kJ mol-1
Oh yeah, because of the decrease in temperature? Thanks
6. (Original post by charco)
Energy change is given by E = mcΔT
Then divide by the number of moles of solute used to give energy change per mol.
Thanks very much that makes sense!

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