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# Determining the empirical formula of magnesium oxide lab

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Introduction

Determining the Empirical formula of Magnesium Oxide Folawiyo Laditi etermine the empirical formula of maglculate the empirical formula of the oxide Masses and Qualitative data Observed throughout the experiment: Trial Number Mass of crucible (g) �0.01ical formula of Magnesium Oxide Mass of crucible and magnesium ribbon (g) �0.01 Mass of crucible and Magnesium ribbon after combustion (g) �0.01 Qualitative Observations 1 9.39 9.49 9.56 -Lid for crucible smaller than it so some air may have leaked in -flame was bending, not directly under crucible -white substance that crumbled easily left in place of magnesium ribbon -the magnesium ribbon itself was slightly lustrous, very thin and malleable 2 9.42 9.55 10.02 -lid smaller than crucible so air may have leaked in -white substance looking nothing like magnesium ribbon left 3 9.44 9.58 -Crucible broke so unable to take the last mass Data Processing: Below are other tables used to help calculate the empirical formula of the oxide: Trial one: Magnesium Oxygen Mass/g 9.49g-9.31g=0.10g 9.56g-9.49g=0.07g Moles /mol 0.10g/24.31gmol-1 =0.004114mol 0.07g/16.00gmol-1 =0.004375 Simplest ratio ...read more.

Middle

This means that the uncertainty for the number of moles of oxygen is �0.001269mol. Table two; After calculations for uncertainties for the moles of both elements were made, the uncertainty for the moles of magnesium was �0.000823mol and the uncertainty for oxygen �0.001269mol Since the uncertainties for the simplest ratios are not relevant, they were not calculated. The percent error for the first trial is: 6% The percent error for the second trial is: Conclusion: The empirical formula for magnesium oxide is MgO1.The empirical formula for one of the trials for this lab had this, but the other Mg6O5, which is relatively close. Even though the percent error for the second experiment seems large, I believe this is due to the fact that very small mass values were being worked with, as well as the fact that the percent error could only be calculated through the ratio, whereas the empirical formulas seem to indicate that the data is more accurate. ...read more.

Conclusion

There are a few ways to improve and avoid the above errors. It is unlikely that a more accurate scale could be used but since the experiment works with such small values, this would definitely be more appropriate. Also it would be best to use another crucible or completely clean out the original in order to avoid the error from the second trial. I think the experiment should be completely more times to make more accurate assumptions as to whether or not how well the crucible was cleaned after the initial trial had an effect on the second. There is a very slight possibility that incomplete combustion did not occur, but increase the accuracy of the experiment it would be best to expose the magnesium as much as possible to oxygen. There may also be impurities in the magnesium ribbon, despite the fact that it was cleaned with steel wool. If making sure the sample was purely magnesium that should be taken into account as well. 1 (TrueKnowledge, 2011)http://www.trueknowledge.com/q/what_is_the_chemical_formula_for_%22magnesium_oxide%22) ?? ?? ?? ?? ...read more.

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