Law of Constant Composition Lab Essay

Purpose To determine the share milligram by host in atomic number 12 oxide and to observe if the serving piece is constant quantity by comparing household allows.Hypothesis/Prediction The percent written material by rush of atomic number 12 in milligram oxide will non change significantly with to each one group that conducted the experiment. The musical theme of each bone marrow should stay the same and any differences must be due to approximately erroneousness.MaterialsMagnesium cleanCrucibleCrucible make doClay triangleIron ringRetort standTongsBalance bunsen burnerProcedure1.obtained a strip of magnesium between 30-40 cm long2.coiled magnesium strip into a tight roll3.measured the mass of the crucible and cover4.Added the magnesium strip to the crucible and measured the magnesium, crucible and cover together.5.Partially covered the crucible with the cover and heated it using a Bunsen burner until the magnesium burnd.6.Turned off Bunsen burner.7.waited for combus tion to proceed8.when the reaction appeared completed, heated the crucible again for another basketball team minutes9.allowed crucible to cool for ten minutes10.measured the mass of the crucible, cover and magnesium oxideObservationsWhen ignited, the magnesium strip gave off a bright light.There was a polish change on the magnesium.It started out as silver and turned into a white colour.The combustion gave off a distinct odour.The end result was a white powder but some magnesium had been leave in its original shape.According to the conjecture of J.L. Proust, a compound constantly has the same character objet dart no matter how it is prepared. For all triad of our own individual groups trials, we obtained the same percentage composition and this satisfies Prousts theory.This is also undefiled with what we collapse read in the textbook Chemistry 11 on the Law of Definite Proportions on pages 147 150.2.What conclusion can you make upon the class results?The conclusions I can make based upon the class results are that the composition of a compound must vary because e rattlingone had a different answer. In most cases, the percent composition of magnesium in the compound was very different from what my group achieved. However, sometimes, the classes results were quite similar to my own.The theory that C.M. Berthollet introduced about the composition of a compound was that a compound has an infinite number of compositions depending on the proportions of the components that were utilise in its preparation. His theory satisfies the results obtained from the whole class. Since every group had a different amount of magnesium they must also bewilder had a different composition of magnesium in the compound multifariousnessed, magnesium oxide.However, this is self-contradictory with what we have been taught and with what is written in the textbook. Since the textbook is a more safe source of information, I must conclude that the reason for this difference in results may be attributed to error on the part of the students conducting the experiment.3.Which French Scientist would you hunt down to support? Explain.The French scientist that I support is J.L. Proust. I equalize with Prousts theory because I accept that if the composition of a cognitive content were to change, so would its properties. An straightforward example of this is one stated in the textbook piddle and hydrogen peroxide. The simple addition of a hydrogen atom to the compound of water can make a liquid that is essential to life beseem deadly. Since I know that the percent composition of a particular substance is the same no matter where, how or when it is made, I must agree with J.L Proust and support his theory.Sources of ErrorOne reason why a student may have obtained a higher percentage of magnesium than the rest of the class is during the experiment, mass must have been lost. This could have been done in many ways. Often, the magnesium took too long to ignite and students began to put it straight into the flame to ignite it and then put it back into the crucible. Sometimes, the magnesium wilted and little pieces of it bust off. In addition, the magnesium would sometimes ignite and then extinguish itself. In the constant removal of the magnesium from the crucible, mass was lost in the form of ashes. When mass is lost during the experiment, the total mass of the compound is lower and when the mass of magnesium was separate by the total mass, yielded a higher percent of magnesium.One reason why a student may have obtained a lower percentage of magnesium than the rest of the class is the magnesium did not properly combust. In many cases, the magnesium would extinguish itself and would not burn completely. This resulted in some white powder, ash, and some magnesium dummy up in the same shape that it was when we began the experiment. This suggests that it did not burn with the rest of the magnesium ribbon and therefore, did not form the com pound with oxygen. This would yield in a higher total mass than what it should have been and when the mass of magnesium is divided by the total mass, would give a lower percentage.The following computer science shows the actual percentage of Magnesium in the compound magnesium oxide. mill mass of MgO = 24.3 + 16.0= 40.3For 1.00 mol of MgO%Mg = 24.3 / 40.3 x one hundred= 60.3%Therefore, the actual percentage value of Mg in MgO is 60%The following calculation shows the percentage error for my own groups result% error = (experimental accepted) / accepted x 100= (72 60) / 60 x 100= 20%Therefore the percentage error for my group was 20%.ConclusionBased on the data collected by each group, the composition of a substance must change depending on the proportions of the components that were used in its preparation.However, as explained earlier, the textbook and the properties of matter state otherwise. Scientifically, if the composition of a compound was to change, so would its properties. The results obtained by the class are quite the turnabout of what has already been proven by Proust to be true and therefore, I believe that the evidence obtained by our chemistry class is the result of many mistakes and cannot be used to convey the idea of the Law of Constant Composition which states that the composition of a specific compound is constant.