The empirical formula of a compound is the simplest whole number ratio of the elements in the compound. Determining the empirical formula of a compound can provide important information about its chemical properties and structure. In this lab, we will be determining the empirical formula of magnesium oxide, a compound commonly used in the production of cement and fire retardants.
To begin the lab, a small amount of magnesium metal is weighed and placed in a crucible. A crucible is a small, heat-resistant container that is used to hold substances during heating. The magnesium is then heated to a high temperature, causing it to react with oxygen from the air to form magnesium oxide.
Next, the magnesium oxide is cooled and weighed. The weight of the magnesium oxide is used to calculate the ratio of magnesium to oxygen in the compound. This ratio is then used to determine the empirical formula of magnesium oxide.
To calculate the ratio of magnesium to oxygen, we need to first determine the number of moles of magnesium and oxygen present in the compound. The number of moles can be calculated by dividing the mass of the element by its atomic mass. For example, if the mass of the magnesium is 0.5 grams and the atomic mass of magnesium is 24.3 grams/mole, the number of moles of magnesium would be 0.5/24.3 = 0.02 moles.
Once the number of moles of each element has been calculated, we can determine the ratio of the elements by dividing the number of moles of each element by the smallest number of moles. For example, if the number of moles of magnesium is 0.02 and the number of moles of oxygen is 0.04, the ratio of magnesium to oxygen would be 0.02/0.02 = 1:2.
The empirical formula of a compound is written as the simplest whole number ratio of the elements in the compound. In this case, the empirical formula of magnesium oxide would be written as MgO, indicating that there is one mole of magnesium for every one mole of oxygen in the compound.
Overall, the empirical formula of magnesium oxide can be determined through a series of steps involving the heating and weighing of the compound, the calculation of the number of moles of each element present, and the determination of the ratio of the elements. This information can provide important insights into the chemical properties and structure of the compound.