Magnesium Ribbon Lab

About 80 mL of HCl was obtained and mixed with phenolphthalein. Using a LabQuest unit and Gas Pressure Sensor kit, the HCl mixture was added to the flask with the magnesium ribbon and allowed to react. When reaction was complete, the change of temperature and gas was recorded. This procedure was repeated for different masses of magnesium ribbon (masses found on page 89 of the lab manual). After the completed procedure, moles of H₂ produced in each trial were calculated. (The actual procedure can be found on pages 87-89 of the lab manual)

In the second experiment, a reaction between magnesium and hydrogen chloride was used to produce hydrogen gas, whose volume was measured using a collection over water. Using this method, it was found that the resultant hydrogen gas had a volume

Because it is dangerous to burn magnesium, it is not possible to directly record heat change. Our lab team suggests an indirect way of determining the heat of combustion for magnesium. To accomplish this, we need to perform two separate trials. One uses a solid (powder) version of MgO, while the other uses Mg ribbon. With the results from these, we can use Hess’ Law to determine q=∆H. This provides both a safe and successful way of indirectly determining the heat of combustion for magnesium.

1. Label each substance on seven pieces of paper. Put two pieces of magnesium ribbon on the paper labeled “Magnesium”.

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

2. Obtained a 2-3 cm strip of magnesium metal ribbon and coiled it loosely into a small ball. Added the magnesium metal to the acid in the test tube.

The goal of this experiment was to determine the empirical formula for a hydrate of magnesium sulfate and water. The technique that was used was measure the mass of the hydrate and then apply heat to evaporate the water. Then determine the mass of water that was in the hydrate and the mass of the remaining magnesium sulfate. The equation for the hydrate is determined by calculating the mole to mole ratio of the water and the anhydrous. The resulting formula will be formated as: MgSO4*_H2O

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.

The purpose of this lab was to test the law of definite proportions for the synthesis reaction of combusting magnesium. In this lab, the polished magnesium ribbon was placed in covered crucible and was heated in order for it to react with Oxygen presented in air and in water provided. The result showed that Magnesium oxide formed through chemical reaction was made up of 60.19% magnesium and 39.81% oxygen, which is approximate proportion of both particles in every Magnesium oxide compound. From this lab it can be concluded that the law of definite proportion stating that the elements in a pure compound combine in definite proportion to each other is factual.

3. The third source of error is not knowing for how long to exactly heat the magnesium until it no longer ignites and forms into a white powder of magnesium oxide. In the procedure, it is stated for how long to heat the magnesium, but as the lab went on, it is realized that the magnesium had to be heated for a longer time. This could mean that the magnesium could have been not heated long enough or too little for it to be fully converted into the magnesium oxide product effecting the final results of the lab by having smaller

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

The hydrochloric acid is put into a calorimeter and then the zinc is added after. The lid is closed after the zinc is added and a thermometer is inserted through the lid in order to check the temperature as the reaction takes place . The temperature is measured until the reaction has completed and the highest temperature is used as the final temperature. ∆T is then found by the equation ∆T=Tfinal-Tinitial. Then according using the equation ∆H=mc ∆T+PV. In this lab the pressure remains constant while the volume is changing. In order to calculate the volume the same reaction with the same amount of zinc and hydrochloric acid is used. However, instead of a calorimeter, an erhlenmeyer flask with a balloon put over the top is used. The hydrochloric acid is placed into a flask, the zinc is placed inside the balloon and then sealed over the flask. By dropping the zinc into the flask the reaction occurs. This allows the H₂ gas to be captured in the balloon. The circumference of the balloon is then found. The circumference can then be applied to the equation C=2πr and the radius is determined. Using the radius of the balloon, in the equation V=(4/3)πr³ the volume taken up by the hydrogen gas can be found. The pressure is the pressure of the air which is measured with a barometer. ∆H can be found by multiplying the mass of hydrochloric acid, the specific heat of HCl, and ∆T of the hydrochloric

    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.

During the immersion of the magnesium metal in the hydrochloric acid solution, white bubbles could be seen escaping the surface of the metal as gas was produced during the reaction. Depending on the temperature of the hydrochloric acid and the overall molar concentration, the rate of reaction differed but the same signs were shown. During the reaction between the magnesium metal and higher concentrations of hydrochloric acid, it was observed that the test tube grew quite warm to the touch. As the immersed magnesium strip sank down, it appeared coated in a layer of white bubbles that fizzed like a carbonated drink. In the lower concentrations of hydrochloric acid, the strip spent some time floating at the surface of the solution in the test tube, later sinking down to the bottom as the

To see if the concentration of hydrochloric acid will increase the rate of the reaction between magnesium ribbon and hydrochloric acid.