Calculating heat given off by burning magnesium?

Heat released in the experiment
= (Heat absorbed by calorimeter) + (Heat absorbed by water)
= (1769 J/⁰C) × (1.126 °C) + (300 g) × (4.18 J/°Cg) × (1.126 °C)
= 3404 J
= 3.404 kJ

Mass of magnesium used
= 0.1375 g

Number of moles of magnesium
= (0.1375 g) / (24.31 g/mol)
= 0.005656 mol

Heat given off by burning magnesium in kJ/g
= (3.404 kJ) / (0.1375 g)
= 24.76 kJ/g

Heat given off by burning magnesium in kJ/mol
= (3.404 kJ) / (0.005656 mol)
= 601.8 kJ/mol