What temperature change will be experienced by the dissolved of NaOH solid?
Chemistry Tutor Site - Homework Problem
A 6.58 g sample of solid sodium hydroxide is dissolved in 127.3 g of water in a perfect calorimeter (no heat is exchanged with the surroundings). What temperature change will be experienced by the solution? The heat of solution for solid sodium hydroxide is -44.5 kJ/mol. Make the added assumption that the heat capacity of the solution is the same as water.
Chemistry Tutor Site - Homework Answer
First we calculate how much heat that produced from the dissolved of NaOH, because it is only 6.58 g of NaOH that used for this experiment. Remember that the heat released from the dissolved NaOH will be equal for the heat that accepted by the water.
mole of NaOH
= 6.58 / 39.998
= 0.165 mol
the heat that produce fom the disssolved NaOH are:
= mol x heat of solution of NaOH
= 0.165 mol x -44.5 kJ/mol
= -7.3425 KJ
= -7342.5 J
The negative sign indicates that the reaction is exothermic and we do not involve this sign into equation below:
q = mc ^T
7342.5 J = 127.3 g x 4.18 J/g.0C x ^T
^T = 13.8 0C
The temperature will be rises 13.8 0C from the initial temperature.
Add comment October 16th, 2008