Determining the Empirical Formula of Magnesium Oxide
Introduction
Chemical formulas imply the arrangement of compounds. Empirical formulas are the simplest whole number ratio of the elements present in a compound (Owen, 2014). However, the actual amount of each type of atom that a compound is consisted of is called the molecular formula. For that reason, the deduction of the empirical formula and the molar mass of a compound is required to determine the molecular formula of the compound.
To determine the empirical formula experimentally, the mass of each element has to be obtained, and converted into its equivalent amount in moles.
In the combustion of magnesium, the product would be magnesium oxide. The recorded mass of the crucible …show more content…
(3) 29.21
Table 2. Table of Qualitative Observation
Qualitative Observation The magnesium ribbon was silver in color and was not malleable before heating The magnesium ribbon first turned gray white in colour and had soon turned into ash after heating.
Data Analysis
The empirical formula of magnesium oxide is able to de determined only after determining the mass and mol of each element within the chemical compound. The empirical formula/simplest ration between the two elements is then established after the manifestation of the mol of each element. Calculating the mass of Magnesium
Mass of magnesium is calculated by obtaining the difference between mass (2) and mass (1).
Mass of magnesium = (2) – (1) = 29.14±0.005g – 29.02±0.005g = 0.12 ± 0.01g (4) Calculating the mass of Oxygen
Mass of oxygen is calculated by obtaining the difference between mass (3) and mass (2).
Mass of oxygen = (3) – (2) = 29.21 ±0.005g – 29.14 ±0.005g = 0.07 ±0.01g (5) Calculating the mol of …show more content…
Evaluation of Experiment
Limitation/Weaknesses Impact on Results Suggestion for Improvements
Opening the lid in order for the oxygen to circulate within the crucible, so as to react with the heated magnesium ribbon to produce magnesium oxide. White ashes (MgO), due to the strong heat, escape from the crucible and cause convectional air within it, which results into the blowing out of the magnesium oxide whenever the lid is opened. This would affect the final mass taken that determines the mass of oxygen reacted with the magnesium. Right after allowing some oxygen to enter the crucible, close the lid immediately to minimize the amount of MgO escaping.
The wavering of values measured from the electronic balance (random error), due to the minor changes in mass. This affects the value shown on the electronic balance as rounding off would occur in the machine. Rounding of the mass would could drastically change the outcome of the ratios, which in return would affect the empirical formula. Due to the fact the error is a random one, it can be reduced by repeating the process several times. The different recorded masses should be averaged to distinguish the final mass. This can guarantee a more precise