The results can be used to find the formula of magnesium oxide and two methods are described for doing so. The challenge in reading these equations comes when the product side has more elements than the reactant side. This lab illustrates 1 the law of conservation of mass and 2 the law of constant composition. Oxygen: All of the elements in group 2 react vigorously with Oxygen, the product of which is an ionic oxide. Experimental Notes Equipment List Caution: Eye protection is essential. Note that there is a progression--each one tells you a little bit more.
Empirical Formula of Magnesium Oxide Chemistry Tutorial Want chemistry games, drills, tests and more? For classes with shorter attention spans, the final step of heating to constant mass could be omitted. If you have to walk with the crucible to the balance, hold the crucible in the tongs and support it with a heat resistant mat under it to take it to the balance for weighing. Apparatus Chemicals Eye protection Per pair or group of students: Crucible with lid Tongs Pipe clay triangle Bunsen burner Tripod Heat resistant mat Emery paper optional Access to: Balance 2 d. A balanced equation shows how mass is conserved because it shows how atoms are conserved. . Safety Wear safety goggles eye protection.
Notice that water consists of two hydrogen atoms and one oxygen atom. Keep your pens, notebooks, etc away from the flame Do not breathe in any fumes coming out of the crucible. From this we can deduce that the ionisation energy decreases as we go down the group. Determine the numbers of electrons which the atoms will lose and gain by applying the. Second, this equation represents the reaction of magnesium with oxygen. They should divide mass by the atomic mass for each element. To write basic chemical equations, you only need to know your reactants, your products and how to write the symbols for them.
Magnesium Nitride: Determine the formula of a compound formed by the reaction of magnesium and nitrogen. From this you can see that Calcium has lost 2 electrons it has gone from 0 to +2 and Oxygen has gained 2 electrons it has gone from 0 to -2. The reaction of magnesium to oxygen is so energetically favorable that burning magnesium can steal the oxygen from both water and carbon dioxide, making these common methods of dousing flames ineffective to stop magnesium combustion. They will also require the relative atomic masses. Open flame will be present. It is better to cool the crucible in a dessicator to remove any moisture, however, in a school laboratory it is not advisable for students to be walking around with hot crucibles, so either keep the crucible in the pipe clay triangle, or, remove the hot crucible using tongs and place it on a nearby heat resistant mat to cool.
Solution: First examine the electron arrangement of the magnesium and nitrogen atoms. You will need a copy of the graph below for the class. Do not look into the crucible when it is heating. Procedure a Cut a piece of magnesium about 10-15 cm long. Recall that the conversion factor relating grams to moles is molar mass.
First of all, do you know that chemical equations are means to express chemical reactions? Do not place anything near the open flame. A magnesium will to form a 2 + ion. Lewis Dots Mg 12 2 - 8 - 2 2 2 O 8 2 - 6 6 6 Write the Lewis symbols for each atom. If time is limited, it is possible to light the magnesium strip inside the crucible and quickly position the lid using tongs before heating the crucible. If the magnesium is tarnished then emery or sand paper will be required to clean it.
The reactants are on the left side, and the products on the right side, with an arrow in the middle to signify the change. It is a white powder. In this experiment, you are using this technique to experimentally determine the empirical formula of magnesium oxide. Lab 2 - Determination of the Empirical Formula of Magnesium Oxide Goal and Overview The quantitative stoichiometric relationships governing mass and amount will be studied using the combustion reaction of magnesium metal. E-mail instructor: Clackamas Community College ©1998, 2002 Clackamas Community College, Hal Bender. Magnesium and oxygen are to separate substances.
Basically there are 10 rules that show which elements and their oxidation numbers take priority in a reaction. Magnesium is reacted with oxygen from the air in a crucible, and the masses before and after the oxidation are measured. Basically, the more electron shielding an atom has the less attracted it's outermost electrons are to the positive nucleus and thus the electrons are lost easier. Repeat this step until the mass readings are consistent. Magnesium oxide is best thought of as an containing magnesium ions and oxide ions. Water may have entered your crucible while it was cooling especially if your lid was not completely covering your crucible , or soot or other particulate matter may have adhered to the top, sides, or lid of your crucible.