Help with molar enthalpy
 

Hi,

I'm having issues with a certain question, and I'm ot getting anywhere with it, I was wondering if someone would be able to?
Here it is:
1.a. A mass of 45.0 g of molten (liquid) silver at its melting point is poured into 750 mL of calorimeter water at 25.0°C. The final temperature reached by both is 30.0°C. If the specific heat capacity of silver is 0.235 kJ/kg•°C, calculate the molar heat of solidification of silver.

Of it's possible would you be able to show me how it's done?

I don't know why they would give you the specific heat capacity? and then ask you to find the moalr enthaply of silver?

molar heat of fusion
 

A mass of 45.0 g of molten (liquid) silver at its melting point is poured into 750 mL of calorimeter water at 25.0°C. The final temperature reached by both is 30.0°C. If the specific heat capacity of silver is 0.235 kJ/kg°C, calculate the molar heat of solidification of silver.

Assuming no heat losses to the environment:
the increase in the water energy = the decrease in the silver energy

Water (1g = 1cm3)

E = mcΔT

E = 0.75 x 4.18 x 5 = 15.675 kJ

Silver

The energy uptake by the water is the sum of the energy released by the silver solidification process + the energy of the silver cooling.

Enthalpy of solidification = mass/RMM x molar enthalpy of solidification

E = 45/107.86 x molar enthalpy of solidification + (0.045 x 0.235 x ΔT)

E = [0.4172 x ΔH] + [0.045 x 0.235 x ΔT]

To proceed further you must know the melting point of silver in order to show ΔT otherwise there are two unknowns.

From the data book Ag melting point = 1234K

Therefore ΔT = 1234 – 303 = 931 degrees

15.675 = 0.4172 x ΔH + [0.045 x 0.235 x 932]

(15.675 – 9.856)/ 0.4172 = ΔH

ΔH = 13.95 kJmol-1