Introduction
John Dalton’s atomic theory states that elements combine in simple numerical ratios to form compounds. A compound, no matter how it is formed, always contains the same elements in the same proportion by weight. The law of mass conservation states that mass can neither be created nor destroyed. In this experiment, the mass of the metal was not destroyed or created; the metal’s mass was simply changed into a compound form once the gas reacted to it.
The net mass of the reactant side of the equation and the product side of the equation should be equal if the experiment is done correctly. The molecular formula represents the number of all elements in a compound. The empirical is the simplest whole number ratio of the elements in that compound.
Combustion reactions always involve oxygen and are almost always exothermic. Exothermic reactions give off energy in heat form. The purpose of this experiment is to find the empirical formula of a compound using whole numbers. To investigate this experiment, the masses of the metal and gas were measured to obtain the empirical formula of the compound.
PROCEDURE
Before starting the experiment, the materials needed were gathered: crucible and lid, Bunsen burner, deionized or distilled water, striker, magnesium ribbon, sandpaper (if needed), clay triangle, wire pad, crucible tongs, electronic scale, ring clamp, experiment stand, paper to record data. Two of each necessary material was gathered in order to conduct two trials at once.
The Essay on Bunson Burner Crucible Experiment Mass
In this experiment we are trying to find the percentage of water in Barium Chloride Dihydiate. During the experiment you must pay close attention to everything done. We are going to try to stay below a 8 percent error. When timing, make sure you only have the crucible over the bunson burner for 10 minutes, no more, no less. Be aware of how dangerous this chemical can be, so please be careful. ...
To prepare for the experiment, the ring clamp was attached to the stand at about 2/3s the way up the stand. The crucible and lid were rinsed with water, dried, and then placed on a clay triangle. The Bunsen burner was hooked up to the gas line and the gas was turned on. The fire was started with the striker and the flame was adjusted to the height of the ring clamp. The crucible and lid were heated gently for 4-6 minutes until the bottom of the crucible became red. The flame was intensified and the crucible and lid were heated for another 10-12 minutes. The crucible and lid were allowed to
cool on the wire pad. The mass of the cooled crucible and lid was recorded using the electronic scale.
This procedure was repeated once more for each trial. In each trial, the ribbon was placed into the crucible and the lid was placed over it. The mass of the crucible, lid and magnesium was recorded. The crucible containing the magnesium was heated gently for 2-3 minutes. The heat was gradually intensified and heated for another 2-3 minutes. One side of the lid was lifted with the crucible tongs to allow the oxygen inside. The metal started glowing. The crucible, lid and compound were heated for another 3 minutes.
The metal was checked periodically until no more glowing was observed. The crucible was then removed from heat and then cooled on the wire pad. 3 drops of deionized water was added to the cooled compound. The crucible was reheated with the lid partially off, allowing the water vapor to escape. The sample was heated slowly and then the heat was intensified for 15-17 minutes. The crucible, lid and compound were allowed to cool on the wire pad. The mass of the crucible, lid and compound was recorded. The sample was reheated for an extra 5 minutes, then the combined mass of the crucible, lid and metal oxide was measured. The metal oxide was disposed of in the proper marked contained and the crucible was cleaned of any residue and rinsed with deionized water.
RESULTS
Units
Trial 1
Trial 2
The Essay on Magnesium Mass Experiment Oxide
Analysis: B) The magnesium strip had turned into a powdered form in which it has degenerated C) 37. 9 grams D) Mg - 50 / 34. 31 = 1. 45 - 1 O - 50 / 16. 0 = 3. 12 - 2 Therefore the ratio will be 1 to 2: MgO 2 E) Based on the evidence the answers are of the ones shown on the above Evaluation: F) The mass of the magnesium oxide would be far too low if there was any magnesium oxide escaping during ...
Before Heating
g
23.860
After 1st Heating
g
21.383
23.859
After 2nd Heating
g
21.385
Mass of Crucible, Lid and Metal
g
21.575
24.054
Mass of Metal
g
0.190
0.195
Mass of Crucible, Lid and Metal Oxide after 1st heating
g
21.646
24.174
2nd Heating Mass Measurement
g
21.648
24.174
Mass of Metal Oxide
g
0.263
0.315
Number of Moles of Metal in the Compound
mol
0.00782
0.00802
Mass of Oxygen in Compound
g
0.0730
0.120
Number of Moles of Oxygen in the Compound
mol
0.00456
0.00750
Simplest Whole Number Ratio of Oxygen to Metal
3:5
14:15
Empirical Formula for the Compound using Whole Numbers
Mg5O3
Mg14O13
DISCUSSION
In order to have magnesium oxide, MgO, the magnesium strip had to be heated. Under normal circumstances, room temperature, magnesium metal, Mg, reacts very slowly with the oxygen, O, in the air. However, as magnesium is heated, it reacts quicker with the oxygen and burns with a white light to produce MgO.
To protect others from the smoke, containing Magnesium Oxide, the crucible had to remain covered. Some magnesium oxide escaped, when the crucible was not covered. The crucible had to be slightly ajar when heating up the magnesium, so that oxygen could get to the reaction. Without oxygen, a fire cannot exist. The shininess of the metal Mg turned to a dull appearance as it changed to MgO. As the magnesium reacted to the oxygen, it also reacted with the nitrogen in the air to form magnesium nitride, Mg3N2.
To expel the nitrogen from the crucible, we added water to the mixture and heated it up. This would cause the Mg3N2, to react with the water, H2O, to form ammonia, NH3, and magnesium hydroxide, Mg(OH)2. The NH3 was driven off during the heating. One sign of this reaction was the ammonia smell given off. This is because upon heating, the Mg(OH)2 would break into MgO and H2O, which would be driven off by the heat. The second reheating was so that any remnants of the Mg(OH)2 of the crucible had been converted to MgO. This was also to have an accurate final mass of our product MgO.
The Essay on Empirical Formula Magnesium Crucible Oxygen
... 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 ... The bottom of the crucible should glow red during the heating. 2. Remove the crucible, using the crucible tongs, and place it ... 2 forming Magnesium Nitrate (Mg 3 N 2). When magnesium metal is burned in pure oxygen, the only product is magnesium oxide. If ...
After the lab, the inside of the crucible was black. This is because the magnesium not only reacted with the oxygen and the nitrogen in the air but also with the porcelain of the crucible. The reason for waiting for the crucible to cool before weighing it was because at higher temperatures, the molecules inside are still active, causing the weight to be off. During Trial 2, the magnesium was not properly burned off and caused the calculations to be off. The magnesium looked as if it had stopped glowing, but the inside coil was not completely burned.
References
www.iun.edu
www.chemistry.about.com
www.universetoday.com/john-daltons-atomic-theory
Lab Experiment
www.purdue.edu
