Balancing Chemical Equations

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Chemical Reaction Noun

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[kem-i-kuhl ree-ak-shun]

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Chemical Reaction

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A process in which the atoms of one or more substances are rearranged to form entirely new, different substances.

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Example: This diagram shows reactants (left) rearranging their atoms to form new products (right), demonstrating that atoms are conserved, which is key to balancing equations.

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Chemical Equation Noun

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

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Chemical Equation

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A symbolic representation of a chemical reaction, showing reactants on the left and products on the right side.

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Example: This balanced chemical equation shows that the number of hydrogen (red) and oxygen (blue) atoms is the same before and after the reaction, conserving mass.

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Reactant Noun

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[ree-ak-tunt]

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Reactant

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The starting substances in a chemical reaction, which are written on the left side of a chemical equation.

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Example: This diagram shows that reactants, like methane and oxygen, are the starting materials on the left side of a chemical equation that are consumed during a reaction.

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Product Noun

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[prod-ukt]

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Product

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The new substances that are formed during a chemical reaction, written on the right side of a chemical equation.

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Example: In a chemical reaction, reactants (left) combine to form new substances called products (right), such as carbon dioxide (CO₂) and water (H₂O).

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Reaction Symbol (→) Noun

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[ree-ak-shun sim-bull]

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Reaction Symbol (→)

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The arrow (→) in a chemical equation that separates reactants from products and means 'yields' or 'produces'.

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Example: The reaction symbol (→) points from the starting materials (reactants) on the left to the new substances (products) on the right, showing the direction of the chemical change.

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Aqueous (aq) Adjective

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[ay-kwee-us]

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Aqueous (aq)

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A state of matter where a substance is dissolved in water, denoted by the symbol (aq) in an equation.

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Example: This diagram shows a solute (particles) evenly mixed into a solvent (liquid) to form a solution, which is what 'aqueous' means for a chemical.

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Law of Conservation of Mass Noun

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

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Law of Conservation of Mass

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The scientific principle stating that matter is neither created nor destroyed during any chemical reaction or physical change.

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Example: This balanced chemical equation shows that the number of atoms for each element is the same before and after the reaction, demonstrating conservation of mass.

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Balanced Equation Noun

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[bal-unsd ee-kway-zhun]

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Balanced Equation

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A chemical equation where the number of atoms for each element is identical on both the reactant and product sides.

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Example: This diagram shows a balanced chemical equation by representing atoms as spheres. It proves the equation is balanced because there are 4 hydrogen and 2 oxygen atoms on both sides.

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Subscript Noun

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[sub-skript]

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Subscript

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A number written after a chemical symbol indicating the number of atoms of that element in one molecule.

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Example: The subscript '2' in the chemical formula CO₂ shows there are two oxygen atoms bonded to one carbon atom in a carbon dioxide molecule.

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Coefficient Noun

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[koh-uh-fish-unt]

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Coefficient

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A number placed in front of a chemical formula that indicates how many molecules are involved in the reaction.

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Example: The coefficient, the number '2', indicates that two molecules of oxygen (O₂) and two molecules of water (H₂O) are involved in the chemical reaction.