‘Aim. To find out the empirical formulae for magnesium-oxide Introduction. The empirical formula of a compound tells us the types of atoms present in a compound as well as the simplest whole-number ratio of the different types of atoms. The empirical formula does not tell us the actual number of atoms in the molecule.
The mass of Mg + the mass of O 2 = mass of Mg xOx. Knowing the mass of magnesium used and the mass of magnesium oxide produced you can determine the mass of oxygen used. The ratio between number of moles of magnesium used and number of moles of oxygen used can be calculated and the empirical formula can be written on the basis of this ratio. Prediction. I predict that magnesium can and will join with oxygen to become magnesium oxide (MgO) because magnesium is in group 2 and can has 2 bands.
Both magnesium and oxygen need to join each other to lose or gain electrons. Magnesium: Oxygen: Mg+O = MgO When magnesium and oxygen coincide they cancel each other out and therefore are completely compatible. Apparatus. 1. Bunsen burner 2. Tripod 3.
Gauze 4. Crucible and Lid 5. Tongs 6. Heatproof mat 7. Safety glasses 8.
Magnesium Diagram. Method. 1. Place a clean, dry crucible (check for any cracks) with its cover on a clay triangle supported by a tripod. Adjust the flame of a Bunsen burner so that the crucible is just above the hot part of the flame. Heat the crucible strongly for five minutes.
... found the empirical formula of magnesium and oxygen. An empirical formula is the ration of atoms in a compound. In this lab the empirical formula for magnesium and oxygen would ... ’s top. After the previous step was completed, the crucible and the Magnesium were heated until white smoke started to protrude from ...
The bottom of the crucible should glow red during the heating. 2. Remove the crucible, using the crucible tongs, and place it on the ceramic pad to cool. After the crucible has cooled to room temperature (this will take about ten minutes), weigh it with its cover on an analytica balance to 0. 001 g. Record the weight on the data sheet.
3. Weigh out 0. 3 g of magnesium and place it into the crucible. Weigh the magnesium, crucible and cover on an analytical balance. Record the weight to 0. 001 g.
4. At frequent intervals, remove the burner and slightly lift the crucible lid using tongs, quickly replacing the lid so as to lose as little magnesium oxide ‘smoke’ as possible. Repeat the process patiently until the magnesium ceases to flare up, then remove the lid and heat strongly to make sure that combustion is complete and all the metal has been converted into oxide. You should not be able to see any shiny metallic surfaces. Allow the crucible to cool then replace the lid and reweigh the whole. Record the mass.
5. Repeat this 5 times so that you will be able to gain an average result. Fair Test. To make this a fair test we weighed the empty crucible and lid before adding magnesium.
This means that the different weights of the crucibles could be accounted for. This allowing any minor errors in the experiments result to be averaged out. To make this a lot more accurate we carried the test out 5 times. Before each time we carried out the experiment we cleaned the crucible and lid thoroughly making sure that there was no excess foreign materials of any sort to tamper with the chemical reaction. Variables.
– The amount of magnesium used in the experiment. – How long it had been left burning for. – How much air you let in it when lifting up the lid. If I were to do this experiment again I would carry it out in a fume cupboard to make sure nothing but pure oxygen will be allowed to come in contact with the burning magnesium. Potential reasons for error Hot Magnesium will react with Nitrogen in the air if there is insufficient O 2 forming Magnesium Nitrate (Mg 3 N 2).
... crucible and the lid from the mass of the crucible and the lid with magnesium in the crucible before the heating process. Average of mass of magnesium: (Crucible + Lid + Magnesium) — (Crucible + Lid) Average of mass ... . The duration of this experiment it is a must to wear safety glasses and lab coat at all times during the lab ...
When magnesium metal is burned in pure oxygen, the only product is magnesium oxide.
If a sample of Mg is weighted before and after combustion, then the increase in mass is equal to the mass of oxygen that is combined with Mg. From a knowledge of the mass of Mg and the mass of combined O, the empirical formula of magnesium oxide can be calculated. There is only one problem with this straight forward approach. It is more usual to burn things in air than in pure oxygen. Air is about 80% nitrogen.
So burning Mg in air results not only in the formation of magnesium oxide, but also a small amount of a “byproduct”, magnesium nitride. Not all the Mg was burned. There is not much to do about this, just make sure that you have followed the method correctly and look out for all the signs of the magnesium being present. I recommend doing this experiment in a fume cupboard so that any products of the combustion do not escape with the gas as you lift up the lid of the crucible to let oxygen in. at lest it will stay in one concentrated area and not around the rest of the room where it wont get used at all. Safety.
As we were dealing with chemicals and heat during the course of this test it was vital that it was carried out with great caution. To achieve this we: – Made sure that the work surface was clean and tidy with no unnecessary objects lying around on it. – Were cautious about burning magnesium as it burns a bright white light, which is possible to blind any one looking straight at it. – Were careful to wear out protective glasses on at all times. – Used tongs to move the equipment about as we were dealing with hot things. – Stood up during the experiment.
– Never left the apparatus unattended and kept a close eye on it at all times noting the changes taking place. – Put the Bunsen burner on the safety flame when not in use to prevent any mishaps – Made sure we didnt inhale any smoke when the magnesium was being burned. Results. Crucible+lid (g) Crucible+lid+Mg (g) Mg (g) Crucible+lid+MgO (g) O (g) 1 19. 9 20. 2 0.
3 20. 4 0. 2 2 25. 2 25. 6 0. 4 25.
9 0. 3 3 24. 8 25. 1 0.
3 25. 3 0. 2 4 16. 3 16. 6 0.
3 16. 8 0. 2 5 11. 8 12. 1 0. 3 12.
3 0. 2 Total Weight (grammes) 1. 6 1. 1 RAM 24 16 Molecules 0.
... this lab was to observe how oxygen can bond with magnesium using extreme heat. The mass of the crucible, cover, and contents was 23 ... it will easily fit into the crucible. Record the mass of the crucible, cover, and magnesium. Place the crucible with the substance in it ... when you burn something, it becomes smaller. The extra mass came from the oxygen in the air. It bonded with the magnesium atoms. ...
07 0. 069 Conclusion. From my results I can tell that 0. 067 molecules of magnesium had combined with 0. 069 moles of oxygen, I predict that 1 mole of magnesium will combine with 0. 069/0.
067 or 1. 031 moles of oxygen. I think that if this experiment had been carried out in a proper laboratory with no interferences you would find that the ratio for this combustion would be very close to 1: 1. Which would justify my prediction to be correct. 38 d.