Investigation for Magnesium Oxide

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.

) Suppose that some magnesium oxide smoke had escaped during the investigation, the Mg:O ratio would have increased from 58% to 72%. The final mass of MgO would have decreased because the magnesium oxide smoke is part of the product and when some of it escapes, it decreases the final mass.

Mole of chlorine : 1.0217g - .221g - .3946 g = .4061 g of chlorine

Hypothesis/Prediction: The percent composition by mass of magnesium in magnesium oxide will not change significantly with each group that conducted the experiment. The composition of each substance should stay the same and any differences must be due to some error.

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

Based on my and other classmates' observations and results it can be proved that every time magnesium combines with oxygen to form Magnesium oxide the percent composition for magnesium will be 60.31% and for oxygen it will be 30.69 % (the results achieved by experiments are

    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.

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)

Using elemental analysis to determine the percent mass composition of each element in a compound is the first step in creating an empirical formula. There are many different types of elemental analysis, but in this experiment gravitational analysis and Beer’s Law are used. Elemental analysis is first used to find the moles of each element, then converted to mass, and then the percent mass of the element in the product is found (2).

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

Experiment 2 focused on finding the enthalpy of solution of magnesium chloride. Testing the enthalpy of solution started with measuring out 10 mL of deionized water in a graduated cylinder for three separate trials, each trial having a different mass of magnesium chloride. The water was then poured into a well of a Styrofoam calorimeter then the initial temperature of water was taken using a temperature probe and the LoggerPro programming. A measured amount of magnesium chloride was placed in the same well as the water in the calorimeter,

A1.Work under the hood! With a pair of tongs, hold a strip of magnesium in a bunsen burner flame. Do not look directly at the flame. Save the ash in a small beaker for the next procedure. If magnesium is substance "A" in the general equation, what is "B"?

To keep a fair test I will have to look into all the variables surrounding the experiment and only change the variable that I am testing on. The other variables are the temperature of the acid at the beginning, the volume of acid, the surface area of the magnesium strip, the length of the magnesium strip and if the magnesium strip is cleaned or not.

The powdered cobalt oxalate hydrate was weighed to about 0.3 g and placed in a pre-weighed crucible. The crucible and the cobalt oxalate were then heated until the cobalt oxalate decomposed into a stable, black solid, or Co3O4. Once the crucible was sufficiently

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