Comments on: How much potassium nitrate has to dissolve in water to absorb 116 kj of heat? http://eatpotassiumrichfood.com/healthy-diet/how-much-potassium-nitrate-has-to-dissolve-in-water-to-absorb-116-kj-of-heat/ A Healthy Eating Guide Thu, 09 Feb 2012 03:13:43 +0000 http://wordpress.org/?v=2.7.1 hourly 1 By: SciMann http://eatpotassiumrichfood.com/healthy-diet/how-much-potassium-nitrate-has-to-dissolve-in-water-to-absorb-116-kj-of-heat/comment-page-1/#comment-6457 SciMann Mon, 08 Feb 2010 09:37:21 +0000 http://eatpotassiumrichfood.com/healthy-diet/how-much-potassium-nitrate-has-to-dissolve-in-water-to-absorb-116-kj-of-heat/#comment-6457 _____Summing dHs ____KNO3 (s) ----___--> KNO3 (bits) -___----> solvated KNO3 (bits) ____________-163.8kcal/mole_________dH= -155.5 kcal/mole dHsolv = -155.5 + 163.8 kcal/mole g KNO3 = MW KNO3 g/mole * (116kJ / 4.186 kJ/kcal) / (-dHsolv kcal/mole) = ?? heat required to solvate KNO3 = 8.34 kcal/mole * 4.186 kJ/kcal = 34.9 kJ/mole Looks like 300-400 g Plug and SOLVE Basic mathematics is a prerequisite to chemistry – I just try to help you with the methodology of solving the problem. _____Summing dHs

____KNO3 (s) —-___–> KNO3 (bits) -___—-> solvated KNO3 (bits)
____________-163.8kcal/mole_________dH= -155.5 kcal/mole
dHsolv = -155.5 + 163.8 kcal/mole

g KNO3 = MW KNO3 g/mole * (116kJ / 4.186 kJ/kcal) / (-dHsolv kcal/mole) = ??

heat required to solvate KNO3 = 8.34 kcal/mole * 4.186 kJ/kcal = 34.9 kJ/mole

Looks like 300-400 g

Plug and SOLVE

Basic mathematics is a prerequisite to chemistry – I just try to help you with the methodology of solving the problem.

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