Modeling Chemical Reactions

Front

Reactants Noun

---

[ree-ak-tants]

Back

Reactants

---

The starting substances present before a chemical reaction begins, typically shown on the left side of a reaction arrow.

---

Example: This diagram shows that reactants, like methane and oxygen, are the starting materials in a chemical reaction that are consumed to form new substances.

Front

Products Noun

---

[prod-ukts]

Back

Products

---

The new substances that are formed as a result of a chemical reaction, shown on the right side of an arrow.

---

Example: In a chemical reaction, the starting materials (reactants) rearrange to form new substances on the right side of the arrow, called the products.

Front

Word Equation Noun

---

[wurd ee-kway-zhun]

Back

Word Equation

---

A representation of a chemical reaction that uses the full names of the elements and compounds involved.

---

Example: This diagram shows a chemical reaction using words to name the reactants (Carbon Dioxide + Water) and the products (Glucose + Oxygen).

Front

Chemical Equation Noun

---

[kem-i-kuhl ee-kway-zhun]

Back

Chemical Equation

---

A representation of a chemical reaction using chemical symbols and formulas instead of words to show reactants and products.

---

Example: This diagram shows a chemical equation by using molecular models to represent reactants (left) rearranging their atoms to form new products (right).

Front

Skeleton Equation Noun

---

[skel-i-tuhn ee-kway-zhun]

Back

Skeleton Equation

---

A chemical equation that shows the correct formulas for reactants and products but does not indicate their relative amounts.

---

Example: This image shows an unbalanced chemical equation (H₂ + O₂ → H₂O), which is a skeleton equation, using both symbols and visual models of the atoms.

Front

Aqueous Solution Noun

---

[ay-kwee-us suh-loo-shun]

Back

Aqueous Solution

---

A solution in which a substance is dissolved in water, designated by the symbol (aq) in a chemical equation.

---

Example: This diagram shows a solute (the particles) evenly mixed into a solvent (the liquid) to form a solution, the basis of an aqueous solution.

Front

Catalyst Noun

---

[kat-l-ist]

Back

Catalyst

---

A substance that increases the rate of a chemical reaction without being consumed by the reaction itself.

---

Example: A catalytic converter uses a catalyst (materials inside) to change harmful car exhaust gases into safer substances, speeding up the chemical reaction without being used up.

Front

Decomposition Reaction Noun

---

[dee-kom-puh-zish-un ree-ak-shun]

Back

Decomposition Reaction

---

A type of chemical reaction in which a single compound breaks down into two or more simpler substances.

---

Example: A large starch molecule (a polysaccharide) is broken down through digestion into many smaller, simpler glucose molecules (monosaccharides), illustrating a decomposition reaction.

Front

Law of Conservation of Mass Noun

---

[law uv kon-ser-vay-shun uv mas]

Back

Law of Conservation of Mass

---

The principle stating that matter is not created or destroyed, meaning reactant mass equals product mass in a reaction.

---

Example: This diagram shows a chemical reaction where atoms are rearranged but not lost. Counting the spheres of each color shows the same number on both sides.

Front

Coefficients Noun

---

[koh-uh-fish-ents]

Back

Coefficients

---

The numbers placed in front of chemical formulas in a balanced equation to indicate the relative number of molecules.

---

Example: The coefficient '2' in front of O₂ and H₂O shows that two molecules of each are needed to balance the chemical reaction.