(Originais Teachy 2023) - Question Medium of Chemistry

The Law of Proust, also known as the Law of Definite Proportions, was established by Joseph Proust and states that in a pure chemical substance, the elements are always present in fixed mass proportions. Consider the reaction between magnesium and oxygen, which forms magnesium oxide (MgO). A student performed this experiment and obtained the following data: 12 g of magnesium (Mg) reacted with 8 g of oxygen (O), forming 20 g of magnesium oxide (MgO). (a) Verify if this reaction obeys the Law of Proust, showing the calculations performed to find the mass proportion of the elements in the reaction. (b) Calculate the mass of oxygen needed to react with 36 g of magnesium and demonstrate how you arrived at this answer. (c) Based on the Law of Proust, determine the mass of magnesium oxide produced from the reaction between 36 g of magnesium and the mass of oxygen found in item (b).