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Post Lab Calculations and Analysis
From the data given, mass of Magnesium = (24.50g -23.93g) = 0.57g,
Mass of the product = (24.55g – 23.93g) = .62g,
According to the law of conservation of mass, the mass of oxygen that combined with magnesium = (0.62g – 0.57g) = 0.05g.
Percentage composition of magnesium oxide:
% Mg of the product =( 0.57 0.62*100) = 91.946%
% oxygen = (100 – 91.946) = 8.046%
Number of moles of each reactant,
Mg = 0.5724 = 0.02375moles
o2 = 0.0531.998. = 0.001563 moles
Mole ratio of Mg: o2 = 0.023750.001563 = 15.1951,
Empirical formula of Magnesium oxide = Mg15O.
The balanced chemical equation for the reaction between magnesium and oxygen
2Mg(s) + o2(g) = 2 MgO (s)
No. of moles of the product produced by Mg reacting completely
= 0.02375moles *1= 0.02375moles
Using the mole ratio of MgO to Mg
Yield = Actual mass of the product (g)Theoretical mass Yield = (0.57g * 40*248 ) = 0.95
% Yield = Actual mass of product (g)Theoretical mass*100= 0.95 * 100 = 95%
In this experiment the following factors could lead to error,
Inaccurate measuring devices for instance in this case, if the mass measuring devices were not sufficiently calibrated, measurement of 24.55, it may have been impossible to measure 24.5500g in this experiment.
Physical state: the physical state of the reactants whether gaseous, liquid or solid could have had an effect on the outcome of the experiment.
Temperature, in this particular experiment, variation in temperature is central to determining the outcome as it affects the rate of reaction.
