The reaction of 0.25 g magnesium with 100 mL of 1 M hydrochloric acid (density d = 1.02 g/ml) raises the temperature of the solution from 20 °C to 35 °C . The specific heat for HCl is 3.93 J/(g.C). Mg (s) + 2HCl (aq) MgCl2 (aq) + H2 (g)
a) Which one of the reagents is the limiting one?
b) Calculate the heat of the reaction. (Use the equation Q = s . m .?T where s is the specific heat, m is the mass of solution and ?T is the change in temperature)
c) Using the above data calculate the enthalpy of the reaction (per 1 mol of magnesium).
d) Is the reaction exothermic or endothermic? Explain.