Law of Constant Composition Lab Essay Essays

Law of Constant Composition Lab Essay Essays Law of Constant Composition Lab Essay Paper Law of Constant Composition Lab Essay Paper Purpose: To find the per centum Mg by mass in Mg oxide and to detect if the per centum composing is changeless by comparing category consequences. Hypothesis/Prediction: The per centum composing by mass of Mg in Mg oxide will non alter significantly with each group that conducted the experiment. The composing of each substance should remain the same and any differences must be due to some mistake. Materials: Magnesium stripCrucibleCrucible coverClay triangleIron ringRetort standTongsBalanceBunsen burnerProcedure:1. obtained a strip of Mg between 30-40 centimeter long2. coiled Mg strip into a tight roll3. measured the mass of the crucible and cover4. Added the Mg strip to the crucible and measured the Mg. crucible and cover together. 5. Partially covered the crucible with the screen and heated it utilizing a Bunsen burner until the Mg ignited. 6. Turned off Bunsen burner. 7. waited for burning to proceed8. when the reaction appeared completed. heated the melting pot once more for another five minutes9. allowed crucible to chill for 10 minutes10. measured the mass of the crucible. screen and magnesium oxideObservations: When ignited. the Mg strip gave off a bright visible radiation. There was a color alteration on the Mg. It started out as Ag and turned into a white coloring material. The burning gave off a distinguishable smell. The terminal consequence was a white pulverization but some Mg had been left in its original form. Harmonizing to the theory of J. L. Proust. a compound ever has the same per centum composing no affair how it is prepared. For all three of our ain single groups tests. we obtained the same per centum composing and this satisfies Prousts theory. This is besides accurate with what we have read in the text edition Chemistry 11 on the Law of Definite Proportions on pages 147 150. 2. What decision can you do upon the category consequences? The decisions I can do based upon the category consequences are that the composing of a compound must change because everyone had a different reply. In most instances. the per centum composing of Mg in the compound was really different from what my group achieved. However. sometimes. the categories consequences were rather similar to my ain. The theory that C. M. Berthollet introduced about the composing of a compound was that a compound has an infinite figure of composings depending on the proportions of the constituents that were used in its readying. His theory satisfies the consequences obtained from the whole category. Since every group had a different sum of Mg they must besides hold had a different composing of Mg in the compound formed. Mg oxide. However. this is inconsistent with what we have been taught and with what is written in the text edition. Since the text edition is a more dependable beginning of information. I must reason that the ground for this difference in consequences may be attributed to error on the portion of the pupils carry oning the experiment. 3. Which Gallic Scientist would you be given to back up? Explain. The Gallic scientist that I support is J. L. Proust. I agree with Marcel prousts theory because I believe that if the composing of a substance were to alter. so would its belongingss. An obvious illustration of this is one stated in the text edition: H2O and H peroxide. The simple add-on of a H atom to the compound of H2O can do a liquid that is indispensable to life go lifelessly. Since I know that the per centum composing of a peculiar substance is the same no affair where. how or when it is made. I must hold with J. L Proust and back up his theory. Beginnings of ErrorOne ground why a pupil may hold obtained a higher per centum of Mg than the remainder of the category is: during the experiment. mass must hold been lost. This could hold been done in many ways. Often. the Mg took excessively long to light and pupils began to set it directly into the fire to light it and so put it back into the crucible. Sometimes. the Mg wilted and small pieces of it broke off. In add-on. the Mg would sometimes light and so snuff out itself. In the changeless remotion of the Mg from the crucible. mass was lost in the signifier of ashes. When mass is lost during the experiment. the entire mass of the compound is lower and when the mass of Mg was divided by the entire mass. yielded a higher per centum of Mg. One ground why a pupil may hold obtained a lower per centum of Mg than the remainder of the category is: the Mg did non decently combust. In many instances. the Mg would snuff out itself and would non fire wholly. This resulted in some white pulverization. ash. and some Mg still in the same form that it was when we began the experiment. This suggests that it did non fire with the remainder of the Mg thread and hence. did non organize the compound with O. This would give in a higher entire mass than what it should hold been and when the mass of Mg is divided by the entire mass. would give a lower per centum. The undermentioned computation shows the existent per centum of Magnesium in the compound Mg oxide. Molar mass of MgO = 24. 3 + 16. 0= 40. 3For 1. 00 mol of MgO: % Mg = 24. 3 / 40. 3 ten 100= 60. 3 % Therefore. the existent per centum value of Mg in MgO is 60 % The undermentioned computation shows the per centum mistake for my ain groups result % mistake = ( experimental accepted ) / accepted ten 100= ( 72 60 ) / 60 ten 100= 20 % Therefore the per centum mistake for my group was 20 % . ConclusionBased on the informations collected by each group. the composing of a substance must alter depending on the proportions of the constituents that were used in its readying. However. as explained earlier. the text edition and the belongingss of affair province otherwise. Scientifically. if the composing of a compound was to alter. so would its belongingss. The consequences obtained by the category are rather the antonym of what has already been proven by Proust to be true and hence. I believe that the grounds obtained by our chemical science category is the consequence of many errors and can non be used to convey the thought of the Law of Constant Composition which states that the composing of a specific compound is changeless.