Consider the dissolution of 2.50 grams of salt xy in 75.0 ml of water within a calorimeter. the temperature of the water decreased by 0.93 oc. the heat capacity of the calorimeter is 42.2 j/oc. the density of the water (and the solution) is 1.00 g/ml. the specific heat capacity of the solution is 4.184 j/goc. calculate the enthalpy change for dissolving this salt on a energy per mass basis (units of j/g).

Answer : The enthalpy change for dissolving this salt on a energy per mass basis is 132.4 J/g

Explanation :

Heat released by the reaction = Heat absorbed by the calorimeter + Heat absorbed by the water

where,

q = heat released by the reaction

= heat absorbed by the calorimeter

= heat absorbed by the water

= specific heat of calorimeter =

= specific heat of water =

= mass of water =

= change in temperature =

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

Now we have to calculate the enthalpy change for dissolving this salt on a energy per mass basis.

where,

= enthalpy change = ?

q = heat released = 331.08 J

m = mass of salt = 2.50 g

Therefore, the enthalpy change for dissolving this salt on a energy per mass basis is 132.4 J/g