Solutions - PowerPoint PPT Presentation

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  1. Solutions

  2. Solution • A solution is a homogeneous mixture in which one substance is dissolved in another substance

  3. Components of a solution • Two parts of a solution: the substance being dissolved (solute) and the substance doing the dissolving (solvent)

  4. Aqueous solution • Solutions in which the solvent is water are aqueous solutions (most common)

  5. Tinctures • A solution in which the solvent is alcohol is a tincture Ex: iodine tincture

  6. Characteristics of a solution • Mixture of two or more substances • light passes through it • particles are uniformly distributed

  7. Ions and dissociation • Ions are atoms with a positive or negative charge

  8. Electrolytes • Solutions that conduct electricity are electrolytes (sodium chloride and silver nitrate)

  9. Non-electrolytes • Non-electrolytes form solutions that do not conduct electricity (sugar, alcohol, benzene)

  10. Questions • What is a solution? • What are the two parts of a solution? • What are three properties of a solution?

  11. Questions • What’s the difference between an aqueous solution and a tincture

  12. Question • If you wanted to dissolve a substance in water as quickly as possible what could you do?

  13. Ways to increase dissolving rate • In order to increase the rate in which a solution dissolves one could heat the solution, stir it, or crush the solute particles

  14. Solubility • The measure of how much solute can be dissolved in a solvent is solubility

  15. What affects solubility? • The three main factors that affect solubility are temperature, type and the amount of the solvent

  16. Effervescence (fizz) • The escape of a gas from a liquid is effervescence (example: soda and alka seltzer)

  17. Concentration • Concentration of a solution is the amount of solute that isdissolved in a solvent

  18. Concentrated vs. dilute • A solution with a lot of solute dissolved is concentrated • A solution with a little solute dissolved is dilute

  19. Types of solutions • A saturated solution contains all the solute it can possibly hold • An unsaturated solution contains less solute that is possible

  20. Supersaturated solution • A supersaturated solution can be made to hold more solute than is normal

  21. Question • Compare a saturated, unsaturated, and a supersaturated solution

  22. Questions • What is solubility and what are the three factors that affect it? • What are three ways to increase the rate in which a solute dissolves?

  23. Water • Water is the universal solvent • A substance that cannot dissolve in water is insoluble

  24. Polar vs. non-polar • A polar molecule has oppositely charged ends (+ and -) • Non-polar molecules have the same charges on its ends

  25. Rule for dissolving solutes in a solvent • Like solutes dissolve in like solvents (polar in polar, non-polar in non-polar)

  26. Hard water vs. soft water • Hard water contains dissolved metal ions • Soft water does not contain dissolved metal ions

  27. Freezing point depression • Lowering the freezing point of a solution as a result of the dissolved solute (freezing point depression) Ex: antifreeze in water

  28. Boiling point elevation • Raising the boiling point of a substance by adding solute (salt in water)

  29. Questions • What is the difference between polar and non-polar molecules? • What is the general rule for dissolving solutes?

  30. Questions • What is the difference between hard and soft water? • How does a solute affect the freezing point and the boiling point?

  31. Suspension • A suspension is a heterogeneous mixture in which the solute particles are large enough to be seen (solute is suspended)

  32. Colloid • A colloid is a homogeneous mixture that is not a true solution (does not separate, solute remains suspended)

  33. Acids • Properties of an acid: sour taste, affecting the color of indicators, turn litmus paper from blue to red, pH 1-6.9

  34. Weak acids vs. strong acids • Weak acids (pH 4 - 6.9) • Strong acids (pH about 1-3; common acids: sulfuric, hydrochloric, nitric, and acetic acids

  35. Bases • Bases are slippery, bitter taste, turn litmus paper from red to blue • pH 7.1-14

  36. Bases • Common bases potassium hydroxide, calcium hydroxide, sodium hydroxide, and ammonium hydroxide

  37. Weak bases vs. strong bases • Weak bases (7.1-10.9 pH) • Strong bases (11-14 pH)

  38. pH scale • Measures hydronium ion concentration (strength of the acid or base) • pH scale ranges from 0-14 (7 is the neutral point) water

  39. Salt • Salt is a compound formed when an acid is mixed with a base (positive ion from a base and a negative ion from an acid)

  40. Neutralization • A neutralization reaction occurs when an acid and a base combine to form salt and water

  41. Precipitate • A precipitate is an insoluble substance crystallizes out of solution (ex: salt from a neutralization reaction)

  42. Precipitation reaction • The process of forming a precipitate is precipitation

  43. Questions • What is the pH scale used for? • What is the pH range for an acid, a base?

  44. Questions • What are some properties of an acid? Of a base? • Describe neutraliztion. • What is a salt?