Sodium bicarbonate is often used as an antacid to neutralize excess hydrochloric acid in an upset stomach. How much hydrochloric acid in grams can be neutralized by \(3.5 \mathrm{~g}\) of sodium bicarbonate? (Hint: Begin by writing a balanced equation for the reaction between aqueous sodium bicarbonate and aqueous hydrochloric acid.)

Chemical reactions are the processes in which substances, known as reactants, transform into new substances, referred to as products. The transformation is governed by the conservation of mass, meaning the total mass of the reactants equals the total mass of the products. In the educational example provided, we examine the chemical reaction where sodium bicarbonate, commonly known as baking soda, reacts with hydrochloric acid to produce sodium chloride (table salt), water, and carbon dioxide gas. This particular reaction is especially important in everyday life, as sodium bicarbonate is often used as an antacid to neutralize the excess stomach acid, providing relief from discomfort.

During the reaction between sodium bicarbonate and hydrochloric acid, a bicarbonate ion reacts with a hydrogen ion to form water and carbon dioxide. The sodium ion and the chloride ion combine to form sodium chloride. This not only demonstrates how a reaction can create different products but also how it can have practical applications in medicine and health. Understanding how this reaction takes place can help students appreciate the relevance of chemistry in real-world situations.

A balanced chemical equation is crucial to accurately describe a chemical reaction. It ensures the law of conservation of mass is adhered to, meaning there must be an equal number of each type of atom on both the reactant side and the product side of the equation. In our example, we balanced the equation:\[\text{NaHCO}_3(aq) + \text{HCl}(aq) \rightarrow \text{NaCl}(aq) + \text{H}_2\text{O}(l) + \text{CO}_2(g)\]

Here, one molecule of sodium bicarbonate reacts with one molecule of hydrochloric acid to produce one molecule of sodium chloride, one molecule of water, and one molecule of carbon dioxide. The balancing process involves fitting coefficients in front of the chemical formulas, so the number of atoms for each element is the same on each side. For students, understanding how to balance equations is fundamental, as it serves as the basis for stoichiometry calculations and is a skill that is widely applicable in all chemistry-related fields.

Stoichiometry calculations are a method of quantifying the amounts of reactants or products in a chemical reaction. These calculations utilize the balanced chemical equation to determine the relationships between the substances involved in the reaction. In our antacid example, the steps provided demonstrate stoichiometry in practice. Starting with a known mass of sodium bicarbonate, we use the molar mass to convert this to moles, a standard unit for the quantity of a substance in chemistry:

\[\text{Moles of NaHCO}_3 = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}}\]

The balanced equation tells us that the moles of sodium bicarbonate are equal to the moles of hydrochloric acid in this reaction. So, once we know the amount of sodium bicarbonate in moles, we can directly determine the moles of hydrochloric acid that can be neutralized.

Understanding Transformation through Stoichiometry

Let's not forget that chemistry is a science of transformation. Stoichiometry not only predicts outcomes but it forms the bridge between the world of individual atoms and molecules and the practical world where chemistry affects our everyday lives. From calculating the right amount of reagents for a lab experiment to scaling up reactions for industrial processes or understanding metabolic pathways in biology, stoichiometry is an indispensable tool in science. Learning and mastering stoichiometry calculations is thus not only about solving textbook problems but about opening the door to the vast applications of chemistry.