Formula of Magnesium Oxide

Authors Avatar

Chemistry Practical Assessment: Finding the formula of Magnesium Oxide (Skill 3)

Results:

Table showing measurements before experiment:

Table showing measurements after experiment:

Mass of products and reactants:

⓵ mass of crucible: 14.21g

⓶ mass of crucible and magnesium before heating: 15.11g

⓷ mass of crucible and magnesium after heating: 15.18g

⓸ mass of magnesium before heating: 0.90g

⓹ mass of magnesium oxide: 0.97g

⓺ mass of oxygen: 0.07g

Changes occurring during the reaction:

  • Magnesium stripe glowed and burned bright orange
  • Sparks appeared on the surface of the magnesium stripe
  • 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.

Join now!

Appearance of contents at the end of experiment:

  • White powder
  • Not in a shape of a coil

Number of moles of magnesium and oxygen in magnesium oxide:

moles =      mass                                                            moles =      mass      

  molar mass                                               ...

This is a preview of the whole essay

Here's what a star student thought of this essay

Avatar

In some places the grammar is not completely correct. For example where the students says ' magnesium might not have reacted completely,' which should have included 'the' beforehand to improve the clarity of the sentence. Spelling, punctuation and grammar are otherwise fine. No sources are referenced which are used in the essay.

The mass decimal places are not consistent throughout the tables which will lose marks on some exam boards. For example in the first table 0.9 should be presented as 0.90. Aside from this, most decimal points are consistent. Improvements and mistakes observed are accurate, but the candidate could have improved their mark by calculating percentage error.

The essay is presented in a clear and concise format which is impressive. Clear subheadings, and easy to read concise information presented in bullet point form are used. The candidate does not show much thinking around the procedure through the initial method, and seems to stick to a strict correct check-box type method which works well in this instance but will not reach the highest marks by not showing the highest levels of reasoning. They could have for example explained further the changes in the metal observed, and accounted for anything that may have confounded the experiment results beforehand. Overall a very correct and well presented essay which just misses out on the higher levels of thinking required to gain top marks.