Reactions in Aqueous Solution

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Aqueous Solution Noun

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[ey-kwee-uhs suh-loo-shuhn]

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Aqueous Solution

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A solution in which the solvent is water, commonly used for many important chemical reactions.

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Example: This diagram shows how a solid ionic compound dissolves in water. The water molecules pull the positive (cation) and negative (anion) ions apart and surround them.

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Ionic Compound Noun

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[ahy-on-ik kom-pound]

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Ionic Compound

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A chemical compound composed of positive and negative ions held together by electrostatic forces.

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Example: This image shows how positive sodium ions (Na+) and negative chloride ions (Cl-) pack together in a repeating crystal structure to form an ionic compound.

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Ion Noun

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[ahy-on]

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Ion

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An atom or molecule that has a net electrical charge due to the loss or gain of one or more electrons.

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Example: A neutral sodium atom, with equal protons and electrons, loses one electron to become a positive sodium ion with an overall positive charge.

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Dissociation Noun

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[dih-soh-see-ey-shuhn]

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Dissociation

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The process where an ionic compound separates into its constituent ions when dissolved in a solvent.

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Example: When an ionic compound like sodium chloride is put in water, it breaks apart (dissociates) into its separate positive and negative ions.

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Solvation Noun

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[sol-vey-shuhn]

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Solvation

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The process in which solvent molecules surround and stabilize solute ions or molecules in a solution.

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Example: Polar water molecules surround charged ions. The negative oxygen end points to the positive ion (Na+), and the positive hydrogen end points to the negative ion (Cl-).

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Solvation Shell Noun

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[sol-vey-shuhn shel]

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Solvation Shell

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The sphere of solvent molecules that surrounds a solute ion or molecule within a solution.

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Example: When an ionic compound dissolves, polar solvent molecules (like water) surround the positive and negative ions, forming a 'solvation shell' based on charge attraction.

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Saturated Solution Noun

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[sach-uh-rey-tid suh-loo-shuhn]

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Saturated Solution

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A solution containing the maximum amount of a solute that can be dissolved at a given temperature and pressure.

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Example: This image shows a saturated solution where a solvent (the liquid) has dissolved the maximum amount of solute (the powder), with excess undissolved solute at the bottom.

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Double-Replacement Reaction Noun

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

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Double-Replacement Reaction

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A chemical reaction where two reactant ionic compounds exchange ions to form two new product compounds.

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Example: This diagram shows two clear solutions, CaCl₂(aq) and Na₂SO₄(aq), mixing to form a solid precipitate (CaSO₄), demonstrating a double-replacement reaction.

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Cation Noun

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[kat-ahy-on]

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Cation

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A positively charged ion, which is formed when a neutral atom loses one or more electrons.

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Example: A neutral sodium atom loses its outer electron, resulting in more protons than electrons and creating a positively charged sodium ion (cation).

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Anion Noun

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[an-ahy-on]

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Anion

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A negatively charged ion, which is formed when a neutral atom gains one or more electrons.

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Example: A neutral chlorine atom gains an electron, filling its outer shell and becoming a negatively charged chloride anion (Cl⁻).