Question

Many over-the-counter antacid tablets are now formulated using calcium carbonate as the active ingredient, which enables such tablets to also be used as dietary calcium supplements. As an antacid for gastric hyperacidity, calcium carbonate reacts by combining with hydrochloric acid found in the stomach, producing a solution of calcium chloride, converting the stomach acid to water, and releasing carbon dioxide gas (which the person suffering from stomach problems may feel as a "burp"). Write the unbalanced chemical equation for this process.

Short answer

The unbalanced chemical equation for the reaction of calcium carbonate with hydrochloric acid to produce calcium chloride, water, and carbon dioxide gas is: \[CaCO_3 + HCl \rightarrow CaCl_2 + H_2O + CO_2\]

Step-by-step solution

Identify the chemical formulas

For this step, we need to know the chemical formulas of the substances involved in the reaction. The chemical formulas of the substances are: - Calcium carbonate: \(CaCO_3\) - Hydrochloric acid: \(HCl\) - Calcium chloride: \(CaCl_2\) - Water: \(H_2O\) - Carbon dioxide: \(CO_2\)

Write the unbalanced chemical equation

Now that we have identified the chemical formulas of all the substances involved in the reaction, we can write the unbalanced chemical equation. An unbalanced chemical equation shows the substances involved in a chemical reaction without accounting for the conservation of mass (the principle that in a chemical reaction, the mass of products must equal the mass of reactants). The unbalanced chemical equation for this process is: \[CaCO_3 + HCl \rightarrow CaCl_2 + H_2O + CO_2\] This equation shows that calcium carbonate (CaCO3) reacts with hydrochloric acid (HCl) to produce calcium chloride (CaCl2), water (H2O), and carbon dioxide gas (CO2), as described in the exercise.

Key concepts

Chemical Equations

A chemical equation is a symbolic representation of a chemical reaction, where reactants are transformed into products through various chemical processes. The equation provides a concise description of the types and amounts of substances involved. For example, let's take the reaction between calcium carbonate and hydrochloric acid. This can be expressed as an unbalanced chemical equation:

calcium carbonate + hydrochloric acid \rightarrow calcium chloride + water + carbon dioxide

This unbalanced equation is written as: \[CaCO_3 + HCl \rightarrow CaCl_2 + H_2O + CO_2\]

It showcases the involved compounds but does not yet respect the laws of conservation of mass or the stoichiometry of the reaction. To refine the understanding, balancing this equation is essential – it's a crucial skill in chemistry, as it ensures that the number of atoms of each element is the same on both sides, upholding the fundamental law that matter cannot be created or destroyed.

Acid-Base Reactions

Acid-base reactions are a type of chemical reaction where an acid reacts with a base to form water and a salt. In the case of our antacid example, hydrochloric acid (HCl) in the stomach reacts with the base calcium carbonate (CaCO3), a common component of antacid tablets. The reaction can be categorized as a neutralization because the acid (HCl) and the base (CaCO3) work together to produce water (H2O) and a salt (calcium chloride - CaCl2), along with carbon dioxide gas (CO2). These reactions are widely applied in everyday life, from culinary arts to pharmaceuticals. Understanding the nature of acids and bases is foundational for explaining various biological and environmental processes.

Stoichiometry

Stoichiometry is a branch of chemistry that deals with the quantitative relationships between reactants and products in a chemical reaction. It's rooted in the law of conservation of mass, which states that mass is neither created nor destroyed in a chemical reaction. As a result, the mass of the reactants must equal the mass of the products. Stoichiometry involves calculating the proportions and amounts of reactants and products, often using a mole ratio derived from the balanced chemical equation. For example, in the reaction involving calcium carbonate and hydrochloric acid, stoichiometry helps us figure out how much hydrochloric acid is needed to completely neutralize a certain amount of calcium carbonate and what volume of carbon dioxide will be produced.

Chemical Formulas

Chemical formulas are shorthand notations used to describe the composition of compounds and molecules. A chemical formula tells us the elements present in a compound and the relative number of atoms of each element. For instance, in the chemical formula for calcium carbonate, \(CaCO_3\), 'Ca' represents calcium, 'C' is carbon, and 'O' stands for oxygen. The subscript '3' following the 'O' indicates that there are three oxygen atoms for every one calcium and one carbon atom in the compound. Understanding chemical formulas is fundamental to communicating the specifics of chemical reactions, as they provide crucial information needed to calculate the amounts of substances required or produced (stoichiometry).