Question

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.

Short answer

(a) \(BaO + H_2O \rightarrow Ba(OH)_2\) (b) \(FeO + 2HClO_4 \rightarrow Fe(ClO_4)_2 + H_2O\) (c) \(SO_3 + H_2O \rightarrow H_2SO_4\) (d) \(CO_2 + 2NaOH \rightarrow Na_2CO_3 + H_2O\)

Step-by-step solution

Understanding the reactants and predicting the products

We need to first identify the reactants given in each reaction and predict the products formed. Each reaction is described below: (a) Barium oxide (BaO) reacts with water (H2O) to form barium hydroxide (Ba(OH)2). (b) Iron(II) oxide (FeO) reacts with perchloric acid (HClO4) to form iron(II) perchlorate (Fe(ClO4)2) and water (H2O). (c) Sulfur trioxide (SO3) reacts with water (H2O) to form sulfuric acid (H2SO4). (d) Carbon dioxide (CO2) reacts with aqueous sodium hydroxide (NaOH) to form sodium carbonate (Na2CO3) and water (H2O). Next, we need to balance these equations to satisfy the law of conservation of mass.

Balancing the equations

(a) BaO + H2O -> Ba(OH)2 The equation is already balanced, with one Ba, two O, and two H atoms on each side. (b) FeO + 2HClO4 -> Fe(ClO4)2 + H2O We need to balance the Cl and O atoms. There are four O atoms and two Cl atoms on the right side, so we put a coefficient of 2 in front of HClO4. Now the equation is balanced with one Fe, two Cl, and six O atoms on each side. (c) SO3 + H2O -> H2SO4 This equation is already balanced, with two H, one S, and four O atoms on each side. (d) CO2 + 2NaOH -> Na2CO3 + H2O We need to balance the Na atoms on both sides of the equation. We put a coefficient of 2 in front of NaOH, making the equation balanced, with one C, three O, and two Na atoms on each side. Here are the balanced equations for the four given reactions: (a) BaO + H2O -> Ba(OH)2 (b) FeO + 2HClO4 -> Fe(ClO4)2 + H2O (c) SO3 + H2O -> H2SO4 (d) CO2 + 2NaOH -> Na2CO3 + H2O

Key concepts

Chemical Reaction Prediction

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

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.

Law of Conservation of Mass

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.