The initial temperature of the water in a constant-pressure calorimeter is 24°c. a reaction takes place in the calorimeter, and the temperature rises to 87°c. the calorimeter contains 367 g of water, which has a specific heat of 4.18 j/(g·°c). calculate the enthalpy change (δh) during this reaction

Answer : The enthalpy change during the reaction is 4.74 kJ/mole

Explanation :

First we have to calculate the heat released during the reaction.

where,

q = heat released = ?

= specific heat of water =

m = mass of water = 367 g

= final temperature of water =

= initial temperature of metal =

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

Thus, the heat released during the reaction = 96.6 kJ

Now we have to calculate the enthalpy change during the reaction.

where,

= enthalpy change = ?

q = heat released = 96.6 kJ

n = number of moles water =

Therefore, the enthalpy change during the reaction is 4.74 kJ/mole

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.