Question

When 60 mL of 1.30 mol/L AgNO3(aq) and 60 mL of 1.30 mol/L HCl(aq) are mixed in a simple calorimeter, the temperature rises by 5.18°C. The molar enthalpy of reaction of HCl(aq) is ab.C kJ/mol.

Answer 1

Answer : The molar enthalpy of reaction is, 33.3 KJ/mole

Explanation :

First we have to calculate the mass of water.

As we know that the density of water is 1 g/ml. So, the mass of water will be:

The volume of water = $60ml+60ml=120ml$

Now we have to calculate the heat absorbed during the reaction.

$q=m\times c\times (\Delta T)$

where,

q = heat absorbed = ?

$c$ = specific heat of water = $4.18J/g^oC$

m = mass of water = 120 g

$\Delta T$ = change in temperature = $5.18^oC$

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

$q=120g\times 4.18J/g^oC\times (5.18)^oC$

$q=2598.288J=2.60KJ$

Now we have to calculate the molar enthalpy of reaction.

$\Delta H=\frac{q}{n}$

where,

$\Delta H$ = enthalpy of neutralization = ?

q = heat released = 2.60 KJ

n = number of moles =

$\Delta H=\frac{2.60KJ}{0.078mole}=33.3KJ/mole$

Therefore, the molar enthalpy of reaction is, 33.3 KJ/mole