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Chemistry Practical Assessment: Finding the formula of Magnesium Oxide (Skill 3) Results: Table showing measurements before experiment: Mass of crucible (g) Mass of lid (g) Mass of magnesium (g) Mass of crucible and magnesium (g) .
Mass of products and reactants: ? mass of crucible: 14. 21g ? mass of crucible and magnesium before heating: 15. 11g ? mass of crucible and magnesium after heating: 15. 18g ? mass of magnesium before heating: 0. 90g ? mass of magnesium oxide: 0. 97g ? mass of oxygen: 0. 07g Changes occurring during the reaction: i?? Magnesium stripe glowed and burned bright orange i?? Sparks appeared on the surface of the magnesium stripe i?? Started to shrink and change into white powder form but still glowing This shows that magnesium has reacted with oxygen to form magnesium oxide, a white powder. Appearance of contents at the end of experiment:
Instead of one mole of magnesium combing with one mole of oxygen, nine moles of magnesium combined with one mole of oxygen. This might be due to the fact that there were some mistakes in my experiment, for example, magnesium might not have reacted completely. Sources of error: i?? While lifting the lid from time to time, the contents inside the crucible might have escaped, so the calculations would be wrong and the mass of the product would be incorrect. i?? The oxidation reaction of magnesium might not be complete, this will affect the mass of the contents and products. i??
Sanding the magnesium stripe might be inconsistent which will result in error in the results due to the fact that there are other substances on the magnesium stripe, this will affect the oxidation reaction. i?? Magnesium in the crucible might also have reacted with other gases in the air, which affects the mass of the products as magnesium didn’t only react with oxygen. i?? There might be a contamination with the crucible residues which might influence the reaction of magnesium and oxygen. i?? Magnesium stripe might have been coiled too tightly when put into the crucible, so not all of it reacted.
Improvements to the method to minimize errors: i?? Use a new crucible, so the contents from previous experiment will not affect the current reaction. i?? Make sure magnesium is not coiled too tightly i?? Sand the magnesium stripe until there are no more rusty surfaces i?? Make sure that the appearance of the magnesium haven’t changed between the times when you open the lid for five minutes before you turn the bunsen burner off Conclusion: In the case of using an actual answer for comparison, I am going to take it from the textbook (page 72 to 73). Table showing actual results: Object Mass (g) Mass of crucible.
14. 63 Mass of crucible and magnesium 14. 87 Mass of crucible and magnesium oxide 15. 03 Mass of magnesium used 0. 24 Mass of oxygen which has reacted with magnesium 0. 16 From the table above, the mass of the crucible and magnesium differ from mines, but it is not of great importance as we used different crucibles and lengths of magnesium. Both our masses of crucible and the contents (magnesium oxide) are the same, with only a difference of 0. 15g. However my mass of oxygen which has reacted with magnesium is a lot less than the actual one, by 0. 09g. For my empirical, instead of being MgO, it is Mg9O.
This shows that nine mole of magnesium combined with one mole of oxygen instead of one mole of magnesium combining with one mole of oxygen. This might be because there are some human errors and mistakes in the experiment. As you can see from my results, the mass of the contents increased after the oxidation reaction. Show preview only The above preview is unformatted text This student written piece of work is one of many that can be found in our GCSE Patterns of Behaviour section. Download this essay Print Save Top Here’s what a star student thought of this essay 4 star(s).