Question

1) A 15.0 g sample of nickel metal is heated to 100.0 C and dropped into 55.0 g of water, initially at 23.0 C. Calculate the final temperature of the nickel and the water, if the specific heat capacity of nickel is 0.444 j / g x C.

2) In a coffee-cup calorimeter, 1.60 g of NH4NO3 is mixed with 75.0 g of water at an initial temperature of 25.00°C. After dissolution of the salt, the final temperature of the calorimeter contents is 23.34°C. Assuming the solution has a heat capacity of 4.18 J/°C·g and assuming no heat loss to the calorimeter, calculate the enthalpy change for the dissolution of NH4NO3 in units of kJ/mol.

Answer 1

1.
[mass H2O x specific heat water x (Tfinal-
Tinitial)] + [mass nickel x specific heat nickel x (Tfinal-Tinitial)] = 0
Solve for Tfinal.

2.
How much heat was exchanged when the NH4NO3 went into solution.
q = mass H2O x specific heat water x (Tfinal-Tinitial) = ??
?? will be J/1.60 g NH4NO3.
Convert that to per mole NH4NO3 and convert that to kJ. The final answer will be kJ/mol.

Answer 2

57667