1 / 112

Chemistry – Matter Unit

Chemistry – Matter Unit. What is matter? What is chemistry? What is the organization of matter? What is the nature of matter?. What is NOT Matter?. Energy !. Types of Energies. Mechanical Chemical Heat Atomic Light Electrical. Is Air matter?.

kimn
Download Presentation

Chemistry – Matter Unit

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Chemistry – Matter Unit • What is matter? • What is chemistry? • What is the organization of matter? • What is the nature of matter?

  2. What is NOT Matter? • Energy !

  3. Types of Energies • Mechanical • Chemical • Heat • Atomic • Light • Electrical

  4. Is Air matter? • What are the two criteria for matter? • Does it take up space? • Does it have mass?

  5. What is chemistry? • “Chemistry is the study of the composition, structure, and the properties of matter and the changes it undergoes.” • All chemical reactions involve energy.

  6. What is the composition of matter? Matter Pure Matter Substance Impure Matter Mixture

  7. What is a pure substance? • A pure substance has a definite composition (proportion). • The composition of a substance will have the same percent of elements no matter where the sample was obtained. • Water from Lake Okechobee and water from the Atlantic Ocean (once cleaned up) will have the same composition of hydrogen to oxygen. • Gold is the same as other gold (once cleaned up).

  8. What is a pure substance? • A puresubstance, by definition, is an element or a compound. • A container with an almost pure compound:

  9. Pure Substance Pure Substance Compound Element

  10. What is an element? • “a pure substance made of only one kind of atom” • A substance that cannot be decomposed any farther by simple chemical means • An element has a definite composition. Gold from South Africa is the same, when purified, as a sample from California.

  11. Periodic Table of Elements • Most elements on the periodic chart are metals. • Elements through 114 but not 113 have been discovered or made.

  12. Elemental Samples • Zinc, copper, lead, carbon, sulfur

  13. What is a compound? • “A compound is a substance that is made from the atoms of two or more elements that are chemically bonded.” • The definition is actually more involved than this.

  14. What is a compound? • A compound is a substance that cannot be decomposed any farther by simple physical means. • A compound has a definite composition by mass. • A compound is made up of two or more elements chemically combined.

  15. What is a compound? • A compoundno longer has the properties of its constituent elements. • Table salt, NaCl or sodium chloride, is a compound of the element sodium and the element chlorine.

  16. Sodium

  17. Sodium metal • Soft, can be cut with a knife • Shiny • Good conductor of electricity • Very reactive

  18. Sodium in water

  19. Chlorine gas

  20. Chlorine gas • Greenish gas • Poisonous • Heavier than air

  21. Sodium in chlorine gas

  22. Sodium chloride, NaCl • Sodium chloride dissolves in water rather than reacts with water. • Sodium chloride is a white solid, not a poisonous green gas. • Sodium chloride is its own substance with its own properties, not those of either sodium or chlorine.

  23. Samples of Other Compounds • Sucrose (table sugar), Sodium Chloride, Water, Copper(II) sulfate

  24. Colored Compounds • Cobalt(II) chloride, Iron(II) sulfate, Potassium dichromate, Potassium chromate, Nickel(II) nitrate, copper(II) sulfate

  25. What is the composition of matter? Matter Pure Substance Impure Matter Mixture

  26. Impure Matter - Mixture • “A mixture is a blend of two or more kinds of matter, each of which retains its own identity and properties.” • A mixture is made up of two or more substances that are not chemically combined.

  27. Mixtures • Mixtures can be separated by simple physical means. • Two mixtures containing the same substances may not have the same proportions. • Example: Very salty water versus barely salty water. Very sweet sugar water versus slightly sweet sugar water.

  28. Water and Dye Mixture • Two mixtures of the same substances may have different proportions.

  29. Mixtures Mixtures Homogeneous Mixture Heterogeneous Mixture ?

  30. Solutions • Mixtures • Mixture = a blend of two or more kinds of matter, each of which retains its own identity and properties a) homogeneous mixture = a mixture that is uniform in composition throughout Ex: Food coloring and water b) heterogeneous mixture = a mixture that is NOT uniform in composition throughout Ex: Oil and water

  31. Heterogeneous Mixtures • Sand and water on the left and sand and gravel on the right.

  32. Heterogeneous Mixture

  33. Types of Mixtures: 1) solution = a homogeneous mixture 2) suspension = a mixture in which the particles are so large that they settle out unless the mixture is constantly stirred or agitated Heterogeneous mixture Ex: Sand and water • 3) colloid = a mixture consisting of particles that are • intermediate in size between those in solutions and those in suspensions • Heterogeneous mixture • Ex: Milk

  34. Colloidal Suspension • Fog

  35. Tyndall Effect

  36. THE NATURE OF SOLUTIONS: • Solvent= the substance that does the dissolving in a solution a) Typically present in the greatest amount b) Typically a liquid c) Water is the most common or “universal” solvent 2) Solute = substance being dissolved in a solution a) Typically present in the least amount b) Typically a solid

  37. 9 Possible Solution Combinations:

  38. Factors Affecting the Rate of Dissolving (Increase Solution Rate): • 1) Grinding: increases surface area • 2) Stirring: allows solvent continual contact with solute • 3) Heating: increases kinetic energy; increases mixing

  39. SOLUBILITY: 1) Solubility = quantity of solute that will dissolve in specific amount of solvent at a certain temperature. (pressure must also be specified for gases). • Ex: 204 g of sugar will dissolve in 100 g of water at 20°C • solubleand insoluble are relative terms • solubility should NOT be confused with the rate at which a substance dissolves 2) saturated solution = a stable solution in which the maximum amount of solute has been dissolved.

  40. 3) solution equilibrium = state where the solute is dissolving at the same rate that the solute is coming out of solution (crystallizing). a) Opposing processes of the dissolving and crystallizing of a solute occur at equal rates. b) solute + solvent solution

  41. 4) unsaturated solution = a solution that contains less solute than a saturated solution under existing conditions 5) supersaturated solution = a solution that temporarily contains more than the saturation amount of solute than the solvent can hold (unstable)

  42. 3 FACTORS EFFECTING SOLUBILITY: The extent to which a given solute dissolves in a solvent depends on the identity of the solute and solvent and also on the existing conditions of pressure & temperature • 1) Nature of solute and solvent • “Like dissolves like” = rule of thumb for predicting whether or not one substance dissolves in another • • “Alikeness” depends on: • o Intermolecular forces • o Type of bonding o Polarity or nonpolarity of molecules: ionic solutes tend to dissolve in polar solvents but not in nonpolar solvents

  43. Solvent-Solute Combinations:

  44. 2) Pressure: a)Pressure has little effect on the solubility of liquids or solids in liquid solvents. b)The solubility of a gas in a liquid solvent INCREASES when pressure increases. It is a direct relationship.

  45. 3) Temperature: a)The solubility of a gas in a liquid solvent DECREASES with an increase in temperature. b)The solubility of a solid in a liquid solvent MOST OFTEN increases with an increase in temperature. However, solubility changes vary widely with temperature changes sometimes decreasing with temperature increases.

  46. Mixtures vs. Compounds • Rocks are mixtures. • Minerals are pure substances • Granite rock

  47. Mixtures vs Compounds • Minerals are pure substances although many have impuities that must be cleaned up first.

  48. Minerals Amethyst Halite Diamond

More Related