Formulas of Hydrates

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Hydrate Noun

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[hy-dreyt]

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Hydrate

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A compound that has a specific number of water molecules chemically bound to its atoms within its crystal structure.

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Example: Heating a hydrate, like the copper sulfate in the crucible, removes its trapped water molecules, a process used to find the hydrate's chemical formula.

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Water of hydration Noun

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[waw-ter uv hy-drey-shuhn]

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Water of hydration

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Water molecules that are chemically bound to a compound's atoms and are incorporated into its crystalline structure.

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Example: Heating a blue copper sulphate crystal (a hydrate) in a test tube causes the water of hydration to be released and form visible water droplets.

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Anhydrous compound Noun

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[an-hy-druhs kom-pound]

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Anhydrous compound

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A substance from which the water of hydration has been removed, often by heating, leaving it in a water-free state.

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Example: This diagram shows that an anhydrous compound, like barium chloride (BaCl₂), is a substance without water. It becomes a hydrate (BaCl₂·2H₂O) by chemically adding water.

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Desiccant Noun

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[des-i-kuhnt]

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Desiccant

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A hygroscopic substance used as a drying agent that absorbs moisture from the air to maintain a dry environment.

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Example: Desiccant packets contain substances like silica gel that absorb water from the air, a process shown by the indicator beads changing color upon becoming hydrated.

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Desiccator Noun

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[des-i-key-ter]

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Desiccator

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A sealable enclosure containing a desiccant, used for preserving moisture-sensitive items by creating a dry atmosphere.

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Example: This image shows a desiccator, a sealed container used in chemistry labs to keep substances dry or remove moisture, which is important for hydrate experiments.

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Mole Noun

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[mohl]

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Mole

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The SI unit for the amount of a substance, representing 6.022 x 10^23 representative particles, such as atoms or molecules.

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Example: This image defines a mole as Avogadro's number (6.022 x 10^23) and shows a physical example: one mole of carbon-12 has a mass of 12 grams.

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Avogadro's number Noun

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[av-uh-gah-drohz nuhm-ber]

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Avogadro's number

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The number of particles in one mole of a substance, precisely defined as 6.022 x 10^23 representative particles.

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Example: This image shows that a 12-gram sample of carbon contains a specific, very large number of atoms, which is known as Avogadro's number (6.022 x 10^23).

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Molar mass Noun

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[moh-ler mas]

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Molar mass

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The mass in grams of one mole of a pure substance, which is numerically equal to its formula weight in AMU.

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Example: The molar mass of a molecule (H₂O) is calculated by adding the atomic masses of its individual atoms (two hydrogens and one oxygen).

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Percent composition Noun

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[per-sent kom-puh-zish-uhn]

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Percent composition

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The percentage by mass of each element present in a compound, which helps determine the compound's empirical formula.

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Example: This image shows the equation used to find the percent composition, which tells you how much of a compound's total mass is made up of one specific element.

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Empirical formula Noun

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[em-pir-i-kuhl fawr-myuh-luh]

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Empirical formula

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A chemical formula showing the simplest whole-number ratio of atoms or moles of elements present in a compound.

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Example: This table shows how an empirical formula is the simplest whole-number ratio of atoms from a molecular formula, like simplifying P₄O₁₀ to P₂O₅.