Question

Complete and balance each acid-base equation. a. \(\mathrm{HI}(a q)+\mathrm{LiOH}(a q) \longrightarrow\) b. \(\mathrm{HC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}(a q)+\mathrm{Ca}(\mathrm{OH})_{2}(a q) \longrightarrow\) c. \(\mathrm{HCl}(a q)+\mathrm{Ba}(\mathrm{OH})_{2}(a q) \longrightarrow\)

Short answer

a. HI(aq) + LiOH(aq) → LiI(aq) + H2O(l), b. 2 HC2H3O2(aq) + Ca(OH)2(aq) → Ca(C2H3O2)2(aq) + 2 H2O(l), c. 2 HCl(aq) + Ba(OH)2(aq) → BaCl2(aq) + 2 H2O(l)

Step-by-step solution

Identify the Products of Acid-Base Reaction

An acid reacts with a base to produce a salt and water. The general equation for an acid-base reaction is: Acid + Base → Salt + Water. Hydroiodic acid (HI) is a strong acid and lithium hydroxide (LiOH) is a strong base, so they react to form a salt (lithium iodide, LiI) and water (H2O). Acetic acid (HC2H3O2) is a weak acid and calcium hydroxide (Ca(OH)2) is a strong base, forming a salt (calcium acetate, Ca(C2H3O2)2) and water. Hydrochloric acid (HCl) is a strong acid and barium hydroxide (Ba(OH)2) is a strong base; the products are the salt (barium chloride, BaCl2) and water. Write these expected products next to each reaction.

Balance the Hydrogen and Oxygen Atoms

Ensure there are the same number of hydrogen (H) and oxygen (O) atoms on both sides of the equation. For reaction (a), there is one hydrogen atom and one oxygen atom on each side, so it's already balanced. For reactions (b) and (c), ensure that the number of hydroxide ions from the base equals the number of hydrogen ions from the acid, which will balance the number of water molecules produced.

Balance the Equations

Use coefficients to balance the number of atoms of each element on both sides of the equations. For (a), no coefficients are needed as the equation is already balanced. For (b), since there are two hydroxide (OH) groups in Ca(OH)2, two molecules of HC2H3O2 are needed to balance both the hydrogen and acetate ions. For (c), one molecule of HCl will react with one hydroxide ion from Ba(OH)2, so two molecules of HCl are needed for every one molecule of Ba(OH)2 to balance the reaction.

Key concepts

Balancing Chemical Equations

Balancing chemical equations is a fundamental skill in chemistry. It ensures that the same number of each type of atom is present on both sides of the equation, following the Law of Conservation of Mass. Imagine you have a recipe that requires the same amount of ingredients in order to make the perfect dish. Just like in cooking, the 'recipe' for a chemical reaction must be balanced to get the right product.

To balance an equation effectively, follow these steps: Begin by listing all the reactants and products. Then tally the number of atoms for each element present in the reactants and compare it to the number in the products. Use coefficients, which are whole numbers placed in front of the compounds, to adjust the number of atoms until they match on both sides.

For example, when hydroiodic acid (HI) reacts with lithium hydroxide (LiOH), you can start by writing the reactants and expected products: HI + LiOH → LiI + H2O. Then, count the number of H, I, Li, and O atoms on both sides to confirm if the equation is balanced. Since there is one of each atom on both the reactant and product sides, no further steps are needed—this equation is already balanced.

Acid-base Neutralization

Acid-base neutralization is like a dance between two partners, an acid and a base, where they combine to cancel out each other's characteristic properties, resulting in the formation of water and a salt. The acids don a proton (H+) hat, and bases wear hydroxide (OH-) shoes. When they 'dance' together, their distinctive items pair up to create water (H2O) and leave behind a 'salt', which is an ionic compound.

Understanding this concept is key for predicting the products of the reaction: an acid (HA) reacts with a base (BOH) to form a salt (BA) and water (H2O). For instance, when acetic acid (HC2H3O2) meets calcium hydroxide (Ca(OH)2), they produce calcium acetate (Ca(C2H3O2)2) and water. It's a beautifully orchestrated process that showcases the transformation of reactive molecules into more stable ones.

Stoichiometry in Chemistry

Stoichiometry is the aspect of chemistry that involves calculations based on the quantities of reactants and products in a chemical reaction. It's like a quantifiable version of the 'if this, then that' approach. In stoichiometry, you use the balanced chemical equation as a blueprint to understand the exact proportions of reactants needed to form the desired products.

It begins with a balanced equation and then dives into the relationships between the reactants and products, based on the mole concept. These calculations can predict the amount of product formed from given quantities of reactants, or how much of one reactant is needed to react completely with another. For example, understanding that it takes two hydrochloric acid (HCl) molecules to react with one barium hydroxide (Ba(OH)2) molecule is an application of stoichiometry. It's a handy tool that prevents you from running out of reactants and ensures that reactions go to completion.