7.14: End of Chapter Key Terms

Solutions, Acids, Bases, and pH

1. Solution: A homogeneous mixture composed of two or more substances, where one substance (solute) is dissolved in another (solvent).
2. Solute: The substance that is dissolved in a solution.
3. Solvent: The substance that dissolves the solute to form a solution; usually the component in greater quantity.
4. Concentration: The amount of solute present in a given quantity of solvent or solution; commonly expressed in molarity (M), which is moles of solute per liter of solution.
5. Molarity (M): A unit of concentration, defined as the number of moles of solute per liter of solution.
6. Solubility: The maximum amount of solute that can dissolve in a given amount of solvent at a specific temperature and pressure.
7. Saturated Solution: A solution that contains the maximum amount of dissolved solute at a given temperature and pressure.
8. Unsaturated Solution: A solution that contains less than the maximum amount of dissolved solute at a given temperature and pressure.
9. Supersaturated Solution: A solution that contains more dissolved solute than it would under normal circumstances, typically achieved by changing the temperature or pressure.
10. Dilution: The process of reducing the concentration of a solute in solution, usually by adding more solvent.
11. Acid: A substance that donates hydrogen ions (H⁺) in an aqueous solution; characterized by a sour taste and the ability to turn blue litmus paper red.
12. Base: A substance that accepts hydrogen ions (H⁺) or donates hydroxide ions (OH⁻) in an aqueous solution; characterized by a bitter taste and slippery feel, and the ability to turn red litmus paper blue.
13. pH Scale: A logarithmic scale used to measure the acidity or basicity of a solution, ranging from 0 to 14, where 7 is neutral, values below 7 are acidic, and values above 7 are basic.
14. pH: The negative logarithm of the hydrogen ion concentration in a solution, pH = -log[H⁺].
15. pOH: The negative logarithm of the hydroxide ion concentration in a solution, pOH = -log[OH⁻].
16. pKa: The negative logarithm of the acid dissociation constant (Ka), a measure of the strength of an acid; lower pKa values indicate stronger acids.
17. pKb: The negative logarithm of the base dissociation constant (Kb), a measure of the strength of a base; lower pKb values indicate stronger bases.
18. Buffer: A solution that resists changes in pH upon the addition of small amounts of an acid or base, typically composed of a weak acid and its conjugate base or a weak base and its conjugate acid.
19. Acid-Base Titration: A laboratory technique used to determine the concentration of an acid or base by reacting it with a standard solution of known concentration.
20. Equivalence Point: The point in a titration at which the amount of titrant added is exactly enough to completely neutralize the analyte solution.
21. Indicator: A substance that changes color at a specific pH range, used to determine the endpoint of a titration.
22. Strong Acid: An acid that completely ionizes in aqueous solution (e.g., hydrochloric acid, HCl).
23. Weak Acid: An acid that partially ionizes in aqueous solution (e.g., acetic acid, CH₃COOH).
24. Strong Base: A base that completely dissociates in aqueous solution (e.g., sodium hydroxide, NaOH).
25. Weak Base: A base that partially ionizes or dissociates in aqueous solution (e.g., ammonia, NH₃).
26. Acid Dissociation Constant (Ka): A quantitative measure of the strength of an acid in solution, given by the equilibrium constant for the dissociation of the acid into its conjugate base and a hydrogen ion.
27. Base Dissociation Constant (Kb): A quantitative measure of the strength of a base in solution, given by the equilibrium constant for the dissociation of the base into its conjugate acid and a hydroxide ion.
28. Neutralization Reaction: A chemical reaction in which an acid and a base react to form water and a salt.
29. Salt: An ionic compound formed from the neutralization reaction of an acid and a base.
30. Le Chatelier’s Principle: A principle stating that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium moves to counteract the change.
31. Hydronium Ion (H₃O⁺): A water molecule with an extra proton, representing the form in which hydrogen ions exist in aqueous solution.
32. Autoionization of Water: The process by which water molecules dissociate into hydrogen ions (H⁺) and hydroxide ions (OH⁻), expressed as H2O⇌H++OH−H_2O \rightleftharpoons H^+ + OH^-H2​O⇌H++OH−.
33. Ion Product of Water (Kw): The product of the concentrations of hydrogen ions and hydroxide ions in water, equal to 1.0×10−141.0 \times 10^{-14}1.0×10−14 at 25°C.
34. Standard Solution: A solution of known concentration used in titrations.
35. Molar Mass: The mass of one mole of a substance, usually expressed in grams per mole (g/mol).