When a 3.25g sample of solid sodium hydroxide was dissolved in a calorimeter in 100.0g of water, the temperature rose from 23.9 degrees C to 32.0 degrees C. Calculate the enthalpy change (in kJ/mol NaOH) for the soln process:
NaOH (s)------->Na+ (aq) + OH (aq)
(Assume it's a perfect calorimeter and that the specific heat of the soln is the same as that of pure water.)
thanks to all you chem wizards lol
2006-10-25 17:06:49 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Chemistry
Q = mc delta t
= (100)(4.186)(32-23.9)
= 3390.66 joules
we know that 1 mole of NaOH = 40 grams
If 3.25 grams of NaOH yields 3.39 kJ
then 40 grams would yield 3.39/3.25 * 40 = 41.7 kJ
of course it's exothermic so the enthalpy change would be negative; -41.7 kJ/mol
2006-10-25 17:18:04 · answer #1 · answered by kb27787 2 · 1⤊ 2⤋
Gah! More homework! The point of this is so that you do it, and actually LEARN something. It's not like your teacher was wondering about it, and was too lazy to do it themselves! And such an easy question too!
Integrate the specific heat of water over the temperature change. Thus you get the amount of heat produced.
Divide this by the number of moles of caustic, and presto, enthalpy change.
2006-10-25 17:10:37 · answer #2 · answered by tgypoi 5 · 0⤊ 6⤋
it's 40KJ
2016-11-06 05:34:58 · answer #3 · answered by Angelica 1 · 2⤊ 0⤋