Exothermic and endothermic reactions

A student mixes 40.0 cm³ of 1.00 mol/dm³ copper(II) sulfate solution with excess magnesium powder in a polystyrene cup. The temperature rises by 7.50 °C. Take the mass of solution as 40 g and specific heat capacity as 4.18 J g⁻¹ °C⁻¹. Calculate the heat energy released, in joules.