Determining the Empirical Formula of Magnesium Oxide

3. Carefully felt the sides of the test tube and observed the resulted chemical reaction for about 30 seconds.

Sandpaper was used to remove impurities from the magnesium strips, resulting in a grey strip, with a bit of metallic lustre. The strip of magnesium received was extremely malleable and was easily cut into 1 cm strips and folded into a tiny ball.

2. The second source of error in the lab is when opening the lid of the crucible which allowed smoke of magnesium oxide to escape. During the lab, we removed the lid a couple of times to allow oxygen to enter the crucible so the magnesium reacts with the air to form magnesium oxide. However, the smoke could have easily escaped from the crucible because of the strong force of heat from the laboratory burner. This could have affected the lab results by decreasing the final mass when some of the product have escaped.

Materials:Magnesium stripCrucibleCrucible coverClay triangleIron ringRetort standTongsBalanceBunsen burnerProcedure:1.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

The purpose of this experiment is to identify three unknown solutions through the flame test. To attain this purpose, seven known solutions were first tested for their colors as seen in Table 1. To avoid potential contamination, droplets of solution were placed in a watch glass. The nichrome wire was heated with the flame generated by the Bunsen burner. Then, the wire was dipped into solution on the watch glass.

The first experiment is about the combustion of magnesium after which the ash is formed.

From this table it can be proved that the percentage composition for magnesium and oxygen is relatively similar for every single Magnesium oxide reactions. My classmates had difference of 2%-5% in their results.

    In this lab, a calorimeter was used to find the enthalpy of reaction for two reactions, the first was between magnesium and 1 molar hydrochloric acid, and the second was between magnesium oxide and 1 molar hydrochloric acid. After the enthalpy for both of these were found, Hess’ law was used to find the molar enthalpy of combustion of magnesium, using the enthalpies for the two previous reactions and the enthalpy of formation for water. The enthalpy of reaction for the magnesium + hydrochloric acid reaction was found to be -812.76 kJ. The enthalpy of reaction for the magnesium oxide + hydrochloric acid reaction was found to be -111.06 kJ. These two enthalpies and the enthalpy of formation for water were manipulated and added together using Hess’s law to get the molar enthalpy of combustion of magnesium. It was found that the molar enthalpy of combustion of magnesium was -987.5 kJ/mol. The accepted enthalpy was -601.6 kJ/mol, which means that there is a percent difference of 64%. This percent difference is very high which indicates that this type of experiment is very inefficient for finding the molar enthalpy of combustion of magnesium. Most likely, a there are many errors in this simple calorimeter experiment that make it inefficient for finding the molar enthalpy of combustion of magnesium.

Examine a piece of nichrome wire. On the data sheet, record the color and the luster of the metal. Use a forceps to hold the wire in the flame of your burner for about two minutes (recall where the hottest part of the flame is located). Describe the appearance of the wire while held in the hottest part of the flame. Allow the wire to cool and reexamine it. From your observations, determine if there was a physical or a chemical change. Give specific reasons for your conclusions. Save the nichrome wire for step #2.

Using the crucible tongs, take a magnesium strip and hold it in hot spot (just above the inner cone of fire) on the bunsen burner.

How empirical formula of Magnesium Oxide is obtained by heating Magnesium in the presence of air?

5.3 mL of bromobenzne and 15 mL of anhydrous ether was then placed into the separatory funnel and was shaken and vented in order to mix the solution. Half of the bromobenzene solution was added first into the round bottom flask and as soon as a color change was observed, the remaining half of the bromobenzene was added drop wise into the round bottom flask. The mixture was then refluxed on a heating mantle for 10 minutes until most of the magnesium has been consumed.

Magnesium chloride +hydrogen Pre-test: I have decided to use the water displacement method to collect the gas. While carrying out my pre-test, I performed experiments with different amounts, times, lengths etc in order to establish the most appropriate quantity. I have decided to use magnesium granules instead of magnesium strips and magnesium powder because when I experimented with magnesium strip It took way to long for the gas to be collected.

This created a distance from the hot surface of the crucible from the Bunsen burner thus, not allowing the experiment to conduct. With the magnesium not touching the hot surface, there is a lack of energy for the chemical reaction to happen and not produce magnesium oxide. Another possible experimental error is that when crushing the magnesium oxide to a fine powder with a glass rod, water was used to wash off the magnesium oxide on the rod to get a more accurate mass. However, due to the solution being hot from the Bunsen burner, adding water created evaporation and also resulted in the solution to spill on to the lab bench which affected the mass and calculations. Also, connecting to this experimental error could be that the glass rod was not washed properly with the distilled water leaving some of the fine powder thus, leading to an approximate mass rather than an exact mass.

Using chemical principles that you have learned this year, explain why you used copper wire to make the basket that held the magnesium in place.