Determining the Empirical Formula of Magnesium Oxide Essay example

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Determining the Empirical Formula of Magnesium Oxide

INTRODUCTION:

The empirical formula is the simplest and lowest whole number ratio of the different atoms in a sample of compound. To work out the empirical formula, the value of moles of the different atoms in a compound is needed. Mole is just simply a unit used to measure the amount of atoms, just like how the unit "dozen" is used to measure things such as eggs. One mole is 6×10^23 atoms and this number is called the Avogadro number. The mole can be also defined as the number of atoms in exactly 12g of Carbon.

In this experiment, the magnesium will be heated and this magnesium will react with the oxygen in the air to form magnesium
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7. When the crucible cooled down so that one was able to hold it, the crucible with lid containing the magnesium oxide was measured. The mass was recorded.

RESULTS:

QUANTATIVE RESULTS:

Mass of empty crucible and lid

(g)

Mass of crucible and lid with magnesium

(g)

Mass of crucible and lid with magnesium oxide

(g)

35.40

35.74

35.94

OUALATATIVE RESULTS:

- White fume was coming out of the crucible, when the lid was lifted.

- When the magnesium was first heated, the magnesium was glowing slightly orange, but it turned into a strong glow later.

- Short after the magnesium had started to be heated, the magnesium turned black. However, as the reaction was beginning to finish, the magnesium became an ashy white color.

CALCULATIONS:

Mass of magnesium:

Mass of crucible and lid with magnesium - Mass of empty crucible and lid

35.74g - 35.40g

= 0.34g

Mass of oxygen:

Mass of crucible and lid with magnesium oxide - Mass of crucible and lid with magnesium

35.94g - 35.74g

= 0.2g

Moles of magnesium:

Mass of magnesium

Ar of magnesium

0.34g

24

= 0.014167 (6 D.P)

Moles of oxygen:

Mass of oxygen

Ar of oxygen

0.2g

16

=0.0125

Mole ratio of magnesium : oxygen:

Magnesium : oxygen

0.0141... : 0.0125

0.0125 0.0125

1.1333…
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