A1.50 g sample of solid nh₄no₃ was added to 35.0 ml of water in a styrofoam cup (insulated from the environment) and stirred until it dissolved. the temperature of the solution dropped from 22.7°c to 19.4°c. what is the heat of reaction for dissolving nh₄no₃, expressed in kj/mol?

Answer : The heat of the reaction is, 1.27 kJ/mole

Explanation :

First we have to calculate the heat released.

Formula used :

or,

where,

Q = heat = ?

m = mass of sample = 1.50 g

c = specific heat of water =

= initial temperature  =

= final temperature  =

Now put all the given value in the above formula, we get:

Now we have to calculate the heat of the reaction in kJ/mol.

where,

= enthalpy change = ?

Q = heat released = 0.0238 kJ

n = number of moles NH₄NO₃ =

Therefore, the heat of the reaction is, 1.27 kJ/mole