Question

6 Metallic Mg reacts with hydrochloric acid according to the following equation: Mg (s)+2 HCI (aq) MgCl2 (aq) + H2 (g) The enthalpy change associated with this reaction can be determined with an ice calorimeter. If 14.34 g of ice are melted when 0.2674 g of Mg reacts with excess hydrochloric acid, what is AH (in kJ/mol Mg) for the reaction written above? The heat of fusion of ice is 333 J/g.

Answer 1

14.34 gm of ice melted so, total Enthalpy change SH= mass oficelmice) x Heat of Fusion of icels) - 14:34 próx 3335/cm - 4775.22 I = 4.78 kJ so, Net Heat readesea - 4.78 kg and we have 0.9476gm of my so, Given mars of mg = 0.94769m Molar Mass of Mg = 24.76 gm mole Given mass so mous of mg = Molar Mass 0.2476 24076 0.01 = mole

So, when oro moles of ing added heat vealsed us 4.78 kJ gf we add i mole of Mg in excess ha then total heat vealsed = 4.78 kJ/mole 0.01 /mole = 478 kJ/mole so, DH = 478 kJ Imole