Answer:
Write the balanced chemical equation for the reaction you are performing.
2Mg+ O2 → 2MgO
2.Calculate the mass of magnesium metal used in each trial.
o Trial 1: 26.945-26.691
Mg metal= 0.254 g
o Trial 2: 26.948-26.691
Mg metal= 0.257 g
3.Calculate the actual yield of magnesium oxide for each trial.
o Trial 1: 27.108-26.691
MgO= 0.417 g
o Trial 2: 27.110-26.691
MgO= 0.419 g
4.Magnesium is the limiting reactant in this experiment. Calculate the theoretical yield of MgO for each trial.
o Trial 1: 0.254g*1 mol/24.305g Mg*2mol MgO/2mol Mg*40.305/1g MgO
0.421g MgO
o Trial 2: 0.257g*1 mol/24.305g Mg*2mol MgO/2mol Mg*40.305/1g MgO
0.426g MgO
5.Determine the percent yield of MgO for your experiment for each trial.
o Trial 1: 0.417/0.421*100= 99.1%
o Trial 2: 0.419/0.426*100= 98.4%
6.Determine the average percent yield of MgO for the two trials.
99.1+98.4= 98.8%
Questions and Conclusions:
1. Describe the process that was used in this lab to create magnesium oxide, specifically identifying the type of chemical reaction. Explain why the product had a higher mass than the reactant, and how this relates to conservation of matter.
Mg was heated with O2 to produce MgO. The reaction used to create magnesium oxide was oxidation reaction. It was an oxidation reaction because Mg loss electrons to react with O, magnesium gained O and oxidized to MgO. The product had a higher mass than the reactant because the reactant bonded to O and formed MgO, so the product had a higher mass due to the gain of O atom over the reactant Mg. This relates to conservation of matter, because the mass of products must be the same as the mass of reactants.
2. What sources of error may have contributed to the percent yield not being 100 percent? Think about things that may have led to inaccurate measurements or where the mass of the product could have been lost if this experiment was conducted in a physical laboratory.
Temperature of the Bunsen burner, Magnesium scraped off by steel wool.
3. When conducting this experiment, some procedures call for heating the substance several times and recording the mass after each heating, continuing until the mass values are constant. Explain the purpose of this process and how it might reduce errors.
It might reduce errors by keeping track of all the measurements of weight
