Consider the unbalanced equation for the neutralization of acetic acid: $$ \mathrm{HC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}(a q)+\mathrm{Ca}(\mathrm{OH})_{2}(a q) \longrightarrow \mathrm{H}_{2} \mathrm{O}(l)+\mathrm{Ca}\left(\mathrm{C}_{2} \mathrm{H}_{3} \mathrm{O}_{2}\right)_{2}(a q) $$ Balance the equation and determine how many moles of \(\mathrm{Ca}(\mathrm{OH})_{2}\) are required to completely neutralize \(1.07 \mathrm{~mol}\) of \(\mathrm{HC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}\).

Stoichiometry is the section of chemistry that involves using relationships between reactants and products in a chemical reaction to determine desired quantitative data. In stoichiometry, it’s important to balance the chemical equation to adhere to the law of conservation of mass, which states that matter cannot be created nor destroyed in an ordinary chemical reaction.

For example, in the neutralization reaction provided, we saw that for every one mole of calcium hydroxide \( \mathrm{Ca(OH)_2} \), two moles of acetic acid \( \mathrm{HC_2H_3O_2} \) are required. This relationship is described by the balanced chemical equation. Understanding stoichiometry helps you predict the amounts of substances consumed and produced in a given reaction, allowing for precise calculations in the lab and beyond.

Key to Success in Stoichiometry

• Always start by balancing the chemical equation.
• Write down the mole ratio of reactants and products from the balanced equation.
• Use dimensional analysis to convert between moles, grams, liters, or particles as needed.

Neutralization reactions are specific types of chemical reactions in which an acid and a base react to form water and a salt. Generally, in aqueous solutions, acids are substances that can donate a proton (H+), and bases are substances that can accept a proton or provide a hydroxide ion \(\mathrm{OH}^-\).

In our exercise, acetic acid \(\mathrm{HC_2H_3O_2}\) is neutralized by calcium hydroxide \(\mathrm{Ca(OH)_2}\). Every neutralization reaction between an acid and a base contains the formation of water as a product. The other product is a salt, which in our case is calcium acetate \(\mathrm{Ca(C_2H_3O_2)_2}\).

Importance of Neutralization

• Essential in waste treatment to manage pH.
• Used in agriculture to correct soil acidity.
• Important in medicinal formulations to neutralize stomach acid.

The mole concept is a central pillar in chemistry that provides a way to quantitatively measure substances. One mole represents \(6.022 \times 10^{23}\) entities (Avogadro's number) of any substance, which means a mole of any two substances contains the same number of entities.

Applying the mole concept allows chemists to work with the submicroscopic particles of matter by comparing masses of various substances during a chemical reaction. For instance, when we calculate that 1.07 moles of \(\mathrm{HC_2H_3O_2}\) require 0.535 moles of \(\mathrm{Ca(OH)_2}\) for neutralization, we're using the mole concept to translate the abstract number of particles into a measurable quantity that can be applied in laboratory and industrial settings.

Applying Mole Concept

• Base calculations on Avogadro’s number for converting between atoms, molecules, or ions and moles.
• Use molar mass as a conversion factor between mass and moles.
• Relate volumes of gases at standard temperature and pressure to moles using molar volume (22.4 L/mol at STP).