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 (CaCO_3) with hydrochloric acid (HCl) to produce calcium chloride (CaCl_2), water (H_2O), and carbon dioxide gas (CO_2) is: CaCO_3 + HCl → CaCl_2 + H_2O + CO_2

Step-by-step solution

1. Write the chemical formulas

First, we need to write the chemical formulas for each of the substances involved in the reaction: - Calcium carbonate: CaCO_3 - Hydrochloric acid: HCl - Calcium chloride: CaCl_2 - Water: H_2O - Carbon dioxide: CO_2

2. Write an unbalanced equation using the chemical formulas

Now that we have the chemical formulas for each substance, we can write the unbalanced equation: CaCO_3 + HCl → CaCl_2 + H_2O + CO_2

Key concepts

Understanding Calcium Carbonate

Calcium carbonate is a common substance found in rocks as the minerals calcite and aragonite. It's also the main component of pearls and the shells of marine organisms, snails, and eggs. In its purest form, calcium carbonate is a white powder or colorless crystal that's widely used in everyday products.

One of the most recognizable uses of calcium carbonate is its application in antacid tablets, where its ability to neutralize stomach acid comes into play. The compound is safe for consumption and also serves as a calcium supplement, helping people maintain healthy bones and teeth.

In chemistry, calcium carbonate has the chemical formula \(\text{CaCO}_3\) and is involved in various reactions, particularly those related to the acid-base reactions. When reacted with acids, calcium carbonate produces calcium salts, water, and carbon dioxide gas, a reaction that is not only common in antacids but also is a key process in the formation of caves where carbonic acid in rainwater dissolves limestone.

The Hydrochloric Acid Reaction

Hydrochloric acid (HCl) is a strong, corrosive acid that is a part of gastric acid, produced by cells in the stomach to aid digestion. It's the acidity in gastric juice that helps break down food, but too much acid can lead to discomfort and conditions such as heartburn or indigestion.

The reaction between calcium carbonate and hydrochloric acid is noteworthy for its role both in nature and medicine. When \(\text{CaCO}_3\) reacts with \(\text{HCl}\), a salt (calcium chloride, \(\text{CaCl}_2\)), water (\(\text{H}_2\text{O}\)), and carbon dioxide gas (\(\text{CO}_2\)) are produced. This is a classic example of an acid-carbonate reaction, which is an important concept in chemistry because it illustrates how acids react with carbonates to release carbon dioxide.

Chemical Reaction Balancing

Chemical reactions must be balanced to ensure that the law of conservation of mass is obeyed; this means the number of atoms for each element should be the same on both sides of the equation. Balancing a chemical equation involves adjusting the coefficients (the numbers in front of the chemical formulas) to achieve the same number of each type of atom on both sides.

For the reaction between calcium carbonate and hydrochloric acid, the unbalanced chemical equation is:\[\text{CaCO}_3 + \text{HCl} \rightarrow \text{CaCl}_2 + \text{H}_2\text{O} + \text{CO}_2\] To balance this equation, you'd need to start by counting the atoms of each element on either side of the equation. Then you adjust the coefficients to make the counts equal. The process is systematic and often starts with balancing elements that appear in only one reactant and one product. After some steps of trial and error, you'll arrive at a balanced equation where the number of atoms for each element is equal on both sides. This fundamental skill in chemistry is crucial as it helps in predicting the quantities of substances consumed and produced in a reaction.