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Mass of Mg Mass of MgO Mass of empty calorimeter Mass of calorimeter and soln. a

ID: 511292 • Letter: M

Question

Mass of Mg Mass of MgO Mass of empty calorimeter Mass of calorimeter and soln. after reaction Total mass of solution Initial Temperature Final Temperature (from graph) Delta T Moles of Mg Moles of MgO q (heat evolved by reaction) Delta H (in kJ/mol) Delta H_1 = Average value of Delta H for all runs using Mg = Delta H_2 = Average value of Delta H for all runs using MgO = Delta H degree f(MgO, s) = Percentage error in Delta H degree _f(MgO, s) from accepted value = Include in your report, on a separate sheet, one sample calculation of each quantity marked with an asterisk

Explanation / Answer

moles = mass/molar mass

heat evolved q = mCpdT

m = mass

Cp = specific heat

dT = change in temperature

                          Mg run 1      Mg run 2        MgO run 1        MgO run 2

moles Mg           0.0027          0.0029           

moles MgO                                                     0.0040               0.0041    

q (J)                   6.18               6.37                 5.77                   7.28

dH (kJ/mol)         2.29              2.20                  1.44                   1.77

dH average for Mg runs = 2.245 kJ/mol

dH average for MgO runs = 1.605

dHo (MgO) = -0.64 kJ/mol

Large difference between the literature value and the calculated value is seen in this case.