The Periodic Table

Front

Reactant Noun

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[ree-ak-tant]

Back

Reactant

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A substance present at the start of a chemical reaction that is consumed during the reaction to form products.

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Example: This diagram shows a chemical reaction. The substances that start the reaction, methane (CH₄) and oxygen (O₂), are the reactants.

Front

Product Noun

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[prod-ukt]

Back

Product

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A new substance that is formed as the result of a chemical reaction between reactants.

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Example: This diagram shows reactants (iron powder, hydrochloric acid) combining to form a new substance, the product (gas bubbles), in a chemical reaction.

Front

Chemical Equation Noun

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[kem-i-kuhl ee-kwey-zhuhn]

Back

Chemical Equation

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A symbolic representation of a chemical reaction using formulas for reactants and products.

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Example: This diagram shows a chemical equation where reactant molecules (Methane, Oxygen) rearrange their atoms to form new product molecules (Carbon Dioxide, Water).

Front

Coefficient Noun

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[koh-uh-fish-uhnt]

Back

Coefficient

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A number placed before a chemical formula in an equation that indicates the relative number of molecules or moles.

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Example: The coefficient '2' in front of H₂O means there are two molecules of water produced in the chemical reaction, as shown by the two water models.

Front

Mole Noun

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[mohl]

Back

Mole

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The SI base unit used to measure the amount of a substance, containing approximately 6.022 x 10²³ elementary entities.

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Example: This image shows that one mole is a specific quantity (6.022 x 10^23 particles) and has a specific mass, like 12 grams for the element carbon.

Front

Molar Mass Noun

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[moh-ler mas]

Back

Molar Mass

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The mass of one mole of a substance, typically expressed in grams per mole (g/mol).

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Example: This image shows that the molar mass of a compound (CO2) is calculated by adding the atomic masses of each atom (one Carbon and two Oxygen).

Front

Synthesis Reaction Noun

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[sin-thuh-sis ree-ak-shuhn]

Back

Synthesis Reaction

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A type of chemical reaction where two or more simple substances combine to form a more complex product.

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Example: Two or more simple substances (hydrogen and oxygen molecules) combine to form a single, more complex product (water molecules), illustrating a synthesis reaction.

Front

Decomposition Reaction Noun

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[dee-kom-puh-zish-uhn ree-ak-shuhn]

Back

Decomposition Reaction

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A type of chemical reaction where a single compound breaks down into two or more simpler products.

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Example: This diagram shows electricity from a battery breaking down one compound, water (H₂O), into two simpler substances, hydrogen gas (H₂) and oxygen gas (O₂).

Front

Single-Replacement Reaction Noun

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[sing-guhl ri-pleys-muhnt ree-ak-shuhn]

Back

Single-Replacement Reaction

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A chemical reaction where an element reacts with a compound, displacing another element from the compound.

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Example: A more reactive metal (the iron nail) displaces a less reactive metal (copper) from a solution, causing the iron to dissolve and the copper to form on the nail.

Front

Double-Replacement Reaction Noun

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[duhb-uhl ri-pleys-muhnt ree-ak-shuhn]

Back

Double-Replacement Reaction

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A reaction where the positive and negative ions of two ionic compounds exchange places to form two new compounds.

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Example: This image shows a double-replacement reaction where two liquid compounds, CaCl₂ and Na₂SO₄, are mixed, causing their ions to switch partners and form new compounds.