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* c* (\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* 4.18J/g^oC* (5.18)^oC`

`q=2598.288J=2.60KJ`

Now we have to calculate the molar enthalpy of reaction.

`\Delta H=(q)/(n)`

where,

`\Delta H` = enthalpy of neutralization = ?

q = heat released = 2.60 KJ

n = number of moles =

`\Delta H=(2.60KJ)/(0.078mole)=33.3KJ/mole`

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