Write balanced equations for the following reactions: (a) barium oxide with water, (b) iron(II) oxide with perchloric acid, (c) sulfur trioxide with water, (d) carbon dioxide with aqueous sodium hydroxide.

Predicting the products of chemical reactions is an essential skill in chemistry. It involves understanding how different substances interact based on their chemical properties and the types of bonds they form. For instance, when a metal oxide reacts with water, it generally forms a metal hydroxide, as shown in the reaction between barium oxide and water; BaO + H2O -> Ba(OH)2. In the case of a reaction between an oxide and an acid, like iron(II) oxide with perchloric acid, the products are typically a salt and water, leading to the equation FeO + 2HClO4 -> Fe(ClO4)2 + H2O.

When dealing with more complex compounds like sulfur trioxide and water, it's known that they form an acid, specifically sulfuric acid in this case: SO3 + H2O -> H2SO4. A keen understanding of the reactants' chemical nature helps us to predict that carbon dioxide and sodium hydroxide will yield sodium carbonate and water: CO2 + 2NaOH -> Na2CO3 + H2O. Through practice and studying different types of reactions, students can improve their ability to predict reaction products more accurately.

Stoichiometry is the mathematical relationship between the quantities of reactants and products in a chemical reaction. It is founded upon the balanced chemical equation, which provides the ratio in which substances react and form products. To apply stoichiometry to balance equations, you look at the moles of each element and ensure the same number of atoms of each element appears on both sides of the equation. For instance, in balancing the reaction CO2 + 2NaOH -> Na2CO3 + H2O, we notice that there are two sodium atoms in the sodium carbonate and therefore require two NaOH molecules to balance the equation.

Stoichiometry also allows you to calculate the amount of product formed from given quantities of reactants or vice versa, making it deeply related to practical applications such as determining the yield of a reaction or calculating the necessary amounts of reactants for a complete reaction.

The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction. It is the fundamental principle guiding the balancing of chemical equations. During a chemical reaction, the atoms rearrange, but the total mass of the system remains constant. This is why in balancing the equations provided, attention was paid to ensure that the number of each type of atom on the reactant side is equivalent to that on the product side.

For example, when balancing the equation FeO + 2HClO4 -> Fe(ClO4)2 + H2O, it's crucial to ensure that the atoms of iron, chlorine, and oxygen are conserved. Here, there's one iron, two chlorines, and a total of six oxygens on both sides after balancing. Emphasizing the concept of conservation of mass can significantly aid in understanding why chemical equations must be balanced and how this conservation underpins the quantitative aspect of chemical reactions.