# Calculate the molar enthalpies of reaction occuring in parts A and B

1. Dec 24, 2011

### alia43

1. The problem statement, all variables and given/known data
Part A:
Mass of Mg (s) = 0.31 g
Initial temperature of calorimeter contents = 24.1 C
Finial temperature of calorimeter contents = 36.8 C

Part B:
Mass of MgO (S) = 1.22 g
Initial temperature of calorimeter contents = 24.0 C
Finial temperature of calorimeter contents = 31. 9 C

100.0 ML of HCL used and -601.6 KJ/mol Mg reacted

2. Relevant equations
Calculate the molar enthalpies of reaction occurring Parts A and B.

3. The attempt at a solution
Enthalpy change of reaction = (chemical amount)(molar enthalpy of reaction)
=Enthalpy change or reaction= (0.31g)(1mol/24.31)(-601.1 kJ/mol/1mol)
= -7.665 kJ
= -8 kJ

Enthalpy change of reaction = (chemical amount)(molar enthalpy of reaction)
=Enthalpy change of reaction= (1.22g)(1mol/40.31g)(-601.1 kJ/mol/1mol)
= -18.19 kJ
= -18 kJ
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

Last edited: Dec 24, 2011
2. Dec 24, 2011

### Staff: Mentor

Shouldn't you use q=mcΔT?