Percent Composition Of Magnesium Oxide

A series of gratis IGCSE Chemistry Activities and Experiments (Cambridge IGCSE Chemistry).

Limerick of Magnesium Oxide
This experiment is designed to calculate the formula of magnesium oxide formed when magnesium is heated in a crucible.

Method:
i. Prepare a table for your results.
2. Make clean the magnesium ribbon with sandpaper and coil it tightly.
3. Weigh the crucible and lid. So add the magnesium, replace the lid and counterbalance it again. Record the masses in your table.
4. Identify the crucible on the pipe-clay triangle on the tripod. Oestrus until the base of operations of the crucible is ruby-red hot.
five. Using the tongs, elevator the chapeau very briefly to permit air in. Try to foreclose whatsoever smoke from escaping.
6. Repeat step v until all the magnesium has burnt to magnesium oxide.
7. Proceed heating with the lid off for about 1 minute, to make sure that all the magnesium has reacted. Then let the crucible absurd.
viii. Weigh the crucible, lid and magnesium oxide. Tape the effect in your table.

Results:
1. Discover the mass of:
a) magnesium used
b) magnesium oxide formed
c) oxygen added.
2. Use your data to in i, to calculate the corporeality of magnesium and and the amount of oxygen in your product.
3. Using your answers in 2, calculate the percent composition of magnesium and oxygen in magnesium oxide.
4. The actual % composition past mass of magnesium oxide is: 60% magnesium, twoscore% oxygen. Annotate on any differences betwixt these values and the values you lot obtained in iii.
5. Using your answers in 2, determine the empirical formula of magnesium oxide.

(If you are not certain how to practise the above calculations, refer to the following video on how to calculate the empirical formula magnesium oxide).

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Questions
1. Why is it useful to take more than one set of results to determine the empirical formula of magnesium oxide.
ii. What are probable to be the main sources of fault in this experiment?

Answers

Evidence Solutions
1. Having several sets of results let us to get the average and helps to eliminate errors present in any one set of results.
2. Incomplete reaction of all the magnesium. Loss of magnesium oxide equally a white smoke when lid is lifted.

Empirical Formula and Molecular Formula
The difference between empirical formula and molecular formula.
How to write the empirical formula for a chemical compound when you are given the molecular formula?
Molecular formulas tell you lot how many atoms of each element are in a compound, and empirical formulas tell you the simplest or most reduced ratio of elements in a chemical compound. If a chemical compound'south molecular formula cannot be reduced any more, then the empirical formula is the same every bit the molecular formula. Many compounds with different molecular formula have the aforementioned empirical formula.

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