For the data above, calculate the percent of magnesium (by mass) determined in the experiment, then click here to check your answer. The percent of magnesium (by mass) is based on the mass of magnesium taken and the mass of product which resulted. This compound contains one oxygen atom for each magnesium atom, and so the empirical formula is simply MgO. Since we cannot have '1.016' oxygen atoms, and since there is experimental error in any endeavor, we round off this ratio to the whole number one. This means that the number of oxygen atoms that have combined per magnesium atom is given by the ratioį. On an experimental bases, we have found that 0.01397 moles of magnesium has combined with 0.01419 moles of oxygen. The empirical formula represents the smallest whole number ratio of the types of atoms in a compound. Calculate the number of moles of oxygen atoms contained in 0.2270 g of oxygen, then click here to check your answer.Į. Note that oxygen atoms are found in MgO individually….not as O2 molecules. The number of moles of oxygen atoms contained in 0.2270 g of oxygen (calculated above) is calculated using the atomic mass of oxygen (16.00 g per mole). For the data above, calculate the number of moles of magnesium reacted, then click here to check your answer.

The number of moles of magnesium reacted is based on the mass of magnesium taken and the molar mass of magnesium (24.31 g per mole of Mg). Using the data above, calculate the mass of oxygen reacted with the sample of magnesium taken, and then click here to check your answer. Since the product of your reaction should be pure magnesium oxide (containing magnesium and oxygen), and the initial material taken was pure elemental magnesium, the mass of oxygen reacted should just be the difference in these two masses. For the data listed above, calculate the mass of the product, then click here to check your answer. The mass of product to be used in all subsequent calculations is based on the final mass of the crucible/beaker and contents (after all heatings have been completed) minus the mass of the empty container (before the magnesium was put into it). Note that all masses should be determined to four decimal places on the electronic balance: this results in typically 6 significant figures when the masses of containers are included, which provides for the masses of magnesium and magnesium oxide to be determined to four significant figures. The masses recorded on in Section I, part (c) include the mass of the containers (the mass of the empty containers is recorded in Section I, part (b)). Your answer should be between 0.3 and 0.4 g (if you have a larger number than this, you are including the mass of the beaker).

The mass of magnesium recorded for, Section I, part (a) should be only the mass of the magnesium metal itself (not including the mass of the beaker in which the mass determination was made). Note that the experiment calls for you to determine in a small beaker the initial mass of magnesium metal taken. Suppose the data below were recorded for this experiment (see, Section I).

From these two masses, you calculate the percentage composition of magnesium oxide. Mg + O2 ® magnesium oxideĪfter the magnesium sample has reacted completely, you determine the mass of magnesium oxide product. Magnesium metal reacts with the oxygen (O2) of the air to form magnesium oxide. In this experiment, you precisely weigh a sample of magnesium metal, and then heat the sample in the air.

O2 molar mass