Law of Constant Composition Lab Essay

Goal: To determine the percent magnesium by mass in magnesium oxide and to notice if the percentage composition is constant simply by comparing category results. Hypothesis/Prediction: The percent composition by simply mass of magnesium in magnesium o2 will not change significantly with each group that conducted the experiment.

The make up of each material should stay and virtually any differences has to be due to some error. Supplies: Magnesium stripCrucibleCrucible coverClay triangleIron ringRetort standTongsBalanceBunsen burnerProcedure: 1 ) obtained a strip of magnesium between 30-40 cm long2. coiled magnesium remove into a restricted roll3. scored the mass of the crucible and cover4. Added the magnesium deprive to the crucible and scored the magnesium, crucible and cover together. 5. Somewhat covered the crucible while using cover and heated it using a Bunsen burner until the magnesium captivated. 6. Switched off Bunsen burner.

7. continued to wait for burning to proceed8. when the response appeared completed, heated the crucible again for another five minutes9. allowed crucible to cool intended for ten minutes10. measured the mass from the crucible, cover and magnesium (mg) oxideObservations: When ever ignited, the magnesium tape gave off a bright light. There was a color change for the magnesium. This started out while silver and turned into a white colour.

The combustion gave off a distinct odour. The end result was a white powdered but some magnesium had been left in its unique shape. Based on the theory of J. M. Proust, a compound always has the same percentage composition no matter how it is well prepared.

For all three of our very own individual organizations trials, we all obtained precisely the same percentage make up and this fulfills Prousts theory. This is also accurate with what we now have read in the textbook Chemistry 11 on the Law of Definite Proportions on internet pages 147 150. 2 . What conclusion can you make after the class results?

The results I can generate based upon the class results are the composition of the compound need to vary mainly because everyone had a different solution. In most cases, the percent make up of magnesium in the substance was different from what my group achieved. However , sometimes, the classes results were quite just like my own. The idea that C. M. Berthollet introduced regarding the structure of a compound was that a compound has an infinite quantity of compositions depending on the proportions from the components that have been used in it is preparation. His theory satisfies the results obtained from the entire class.

Seeing that every group had a distinct amount of magnesium they have to also have had a different structure of magnesium in the mixture formed, magnesium (mg) oxide. However , this is sporadic with what we’ve been taught and with what is written in the textbook. Because the textbook is known as a more reliable method to obtain information, I need to conclude which the reason for this difference in results could possibly be attributed to problem on the part of the scholars conducting the experiment. several. Which France Scientist do you tend to support? Explain.

French scientist which i support is usually J. T. Proust. I agree with Prousts theory since I believe that if the make up of a substance were to alter, so could its houses. An obvious example of this is one stated in the textbook: water and hydrogen peroxide.

The straightforward addition of your hydrogen atom to the substance of drinking water can make a the liquid that is essential to life become deadly. As I know the percent composition of a particular substance is the same no matter where, how or when it is built, I must believe J. M Proust and support his theory. Causes of ErrorOne reasons why a student may have obtained a greater percentage of magnesium compared to the rest of the course is: during the experiment, mass must have been lost. This may have been required for many ways. Frequently , the magnesium (mg) took very long to stir up and college students began to place it straight into the flame to ignite it and then restore it into the crucible.

Sometimes, the magnesium wilted and small pieces of it broke away. In addition , the magnesium will sometimes ignite and then wash away itself. Inside the constant removal of the magnesium (mg) from the crucible, mass was lost in the form of ashes. When mass is lost throughout the experiment, the overall mass of the compound is leaner and when the mass of magnesium was divided by the total mass, yielded a higher percent of magnesium. One particular reason why students may have developed a lower percentage of magnesium than the rest of the class is usually: the magnesium did not properly combust.

On many occasions, the magnesium (mg) would reduce itself and would not burn off completely. This kind of resulted in a lot of white powder, ash, and a few magnesium still in the same shape that it was when we began the try things out. This shows that it would not burn with all the rest of the magnesium ribbon and for that reason, did not make up the compound with oxygen. This could yield in a higher total mass than what it should had been and when the mass of magnesium is usually divided by the total mass, would give a lower percentage. The next calculation displays the actual percentage of Magnesium (mg) in the compound magnesium o2.

Molar mass of MgO = twenty four. 3 + 16. 0= 40. 3For 1 . 00 mol of MgO: %Mg = twenty four. 3 / 40. 3 x 100= 70. 3%Therefore, the actual percentage value of Mg in MgO is 60%The following calculation shows the proportion error intended for my own organizations result% mistake = (experimental accepted) as well as accepted by 100= (72 60) as well as 60 times 100= 20%Therefore the percentage problem for my group was 20%. ConclusionBased on the data collected simply by each group, the structure of a substance must change depending on the dimensions of the components that were utilized in its preparation. However , as explained before, the textbook and the properties of subject state normally. Scientifically, if the composition of any compound was going to change, and so would the properties.

The results obtained by the school are quite the opposite of what has already been confirmed by Proust to be the case and therefore, I believe that the data obtained simply by our hormone balance class is the result of many mistakes and cannot be accustomed to convey the idea of the Law of Constant Make up which says that the structure of a particular compound is definitely constant.