Question

the standard enthalpy of formation of MgO lab

please help! thank you

MUST SHOW ALL CALCULATIONS and CORRECT SIGNIFICANT FIGURES. RE NEAT 1. How many grams of hydrochloric acid solution are present in 23.3 mL of that solution? The density of the hydrochloric acid solution is 1.00 g/mL. 2. Convert 0.6319 grams of Mg to moles of Mg. 3. Convert 1.1162 grams of Mgo to moles of Mgo. 4. AH for the reaction MgO (s) + 2 H(aq) What is the AH for Mg2+ (aq) + H2O (I) Mg2+ (aq) + H2O () = -136.5 kJ. MgO (s) + 2 H+ (aq) = ? DID YOU REMEMBER TO SHOW ALL CALCULATIONS AND REPORT THE CORRECT NUMBER OF SIGNIFICANT FIGURES?

Answer 1

1. The volume of hydrochloric acid    = 23.3ml

     The density of solution                   = 1g/ml

mass of hydrochloric acid    = volume * density

                                            = 23.3*1 = 23.3g

2. no of moles of Mg   = W/G.A.Wt

                                   = 0.6319/24   = 0.0263moles

3. molar mass of MgO   = 40g/mole

no of moles of MgO    = W/G.M.Wt

                                   = 1.1162/40   = 0.028moles

4. MgO(s) + 2H^+ (aq) ------------> Mg^2+ (aq) + H2O(l)            $\Delta$H = -136.5KJ

    Mg^2+ (aq) + H2O(l) ----------> MgO(s) + 2H^+ (aq)              $\Delta$H = 136.5KJ