Investigation for Magnesium Oxide

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Hypothesis - The idea I aim to test in this experiment is the relationship between the mass of magnesium and mass of oxygen once the magnesium has been heated and reacted with the oxygen. There will be 3 variables in this experiment. The independent variable will be the mass of magnesium ribbon as different measurements will be taken and used for each trial. The dependant variable will be the mass of Magnesium Oxide, this is a measured variable as the mass of oxygen can be calculated and will enable us to determine the formula for Magnesium Oxide. The controlled variable is that the Magnesium used is possibly from the same ribbon and after being cut into lengths was stored in the same way in plastic containers. Preliminary - I originally did a preliminary test with Iron wool where we used a similar method but Testthe iron wool was held over the flame by tongs and not contained within a crucible. We learnt from this experiment the importance of the crucible to contain all of the metal for an accurate test because the iron wool broke off as it heated and we were left with a lot of the iron wool on the bench mats around the Bunsen burner so our calculation of the mass of iron oxide was not accurate as we had not contained all the wool and couldn’t accurately collect the pieces around that had come away, therefore no giving a true mass of Iron Oxide.

Prediction - I predict that when the magnesium and the Oxygen combine and react together the magnesium will oxidise and become heavier. I expect to see a straight line pattern from these results as I believe the more Magnesium there is the more Oxygen it will take on to form the Magnesium Oxide and so believe the results should gradually get heavier and heavier as the Magnesium gets heavier and heavier. The equation for this investigation would be Mg + O2 MgO which would balance as 2Mg + O2  2MgO. This is done as the Oxygen has two molecules which would need two Magnesium molecules to balance it out. The physical changes I expect to take place are heat and light as I expect the Magnesium to change colour as it is heated up and reacts with the Oxygen. The Chemical changes I expect to take place are that a new substance will be made and a new formula will be formed. A new substance will be made in the form of smoke and the new formula will be MgO. Apparatus - *Goggles*Crucible and Lid

*Bench Mat*Tongs
*Tripod*Varied lengths of Magnesium ribbon
*Bunsen burner*Scales
*Pipe-clay triangle*200g weight

Method - All the apparatus was set up to ensure that the experiment was carried out safely. Goggles were worn and the bench mat was put in place in case any sparks or parts of the experiment went wrong to protect our eyes and the work surface. The tripod and pipe clay triangle were used to keep the crucible safely above the heat. The Bunsen burner was used to heat the magnesium and was set to a fierce blue flame. The crucible held the Magnesium above the Bunsen burner, and the lid contained as much smoke as possible to help the reaction to take place. The crucible lid and tongs were used to occasionally let in the oxygen and then replace the lid safely.

The apparatus was set up as above and as per the diagram to being the experiment. I first checked the scales using a 200g weight to check their accuracy. When I weighed the 200g weight on the scales prior to the experiment the scales weighed in at 1.038kg however, as this was a large weight by comparison to my crucible I didn’t account for this slight measurement in my results as I decided it would make the calculations too low as my crucible was only a fraction of the weight of 200g and so for the purposes of this experiment wouldn’t alter my results enough to justify it. I then measured the crucible without the lid to find out its mass (22.27g), once recorded I then measured the Magnesium ribbon (0.29g) I then measured the two together to check the accuracy and got a mass of 22.56g which...
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