Physical-Chemical Properties Mixtures/Elements/Cmpds

1. Physical-Chemical Properties Mixtures/Elements/Cmpds Adapted from “Matter, Building Block of the Universe” Prentice Hall Made by Jim Barnaby 2004

2. Matter Matter Anything with mass and volume

3. Physical Properties Physical Properties Physical Properties describe objects (matter) and are used to identify and compare different types of matter Color, odor, size, shape, state (phase), texture, hardness, taste, density, boiling point, melting point, freezing point, magnetism, conductivity, conducts heat, mass, weight, volume, solubility …

4. Physical Change Physical Change Change in size, state or shape or changes in other physical properties. One or more physical attributes transform, but the chemical identity is unchanged.

5. Differentiate gases Suppose you have to distinguish between two gases, Oxygen and Hydrogen (O2 & H2). Both are colorless, tasteless and odorless. Since they are gases they have no definite volume. Each has a specific density but you cannot determine volume to get density. Describe a brief procedure you can use to differentiate between the two gases (O2 & H2).

6. Chemical Properties Chemical Properties The properties that describe how a substance changes into other new substances. The tendency of a substance to change chemical identity (transforms into a different substance)

7. Chemical property-change A Chemical Property describes a substance’s ability to change into a different substance, a Chemical Change is the process by which the substance changes. (Example, the ability of a substance to burn is a chemical property, the process of burning is a chemical change)

8. Chemical Reaction Chemical Change (Chemical Reaction) New substances with different properties are formed A substance changes its chemical identity, atoms are re-arranged to produce a new substance with different properties Chemical Reaction New substance is formed by the re-arrangement of atoms

9. Evidence of Chemical Change Evidence of chemical change Color change, rust, exothermic (hot-produces heat energy), endothermic (cold-absorbs heat energy), light, bubbles, burning, explosion (releases energy), flammability—ability to burn

10. Physical or Chemical Change? The main difference between a physical and a chemical change is that a chemical change involves the production of a new substance. Physical changes are easily reversed.

11. Physical or Chemical Physical or Chemical change Light a match Slice a cake into 4 pieces Ice cream melts into mush Alka-seltzer in water Crumple a piece of Al foil Baking soda and vinegar

12. Physical or Chemical Water freezes into ice Water boils Jeans fade in the sun Bleach clothes Digest food A candle melts  List physical properties for clock, table, person, …..etc

13. Demos—Labs Demonstrations:  Roast marshmallows—C12H22O11 draw rxn on the board Complete and turn in metal salts flame lab Investigate aquarium experiment Deep rock jug

14. Grocery Store How is a grocery store (supermarket) set up? Produce, meats, dairy, frozen foods, drinks, …etc  Imagine how hard it would be to find items if there were no organized way of groceries in a grocery store. Frozen pizza next to panty hose…

15. Classification of matter According to makeup, matter is classified into (4 classes): Matter exists as: Mixtures Solutions Elements Compounds

16. Mixture Mixture Matter that consists of two or more substances mixed together but not chemically combined. The substances keep their separate identities and most of their own properties, however their chemical composition does not change.  2 types of mixtures are heterogeneous and homogeneous mixtures

17. Heterogeneous Mixture Heterogeneous mixture Least mixed mixture does not appear to be the same throughout. Parts are easy to recognize and separate. Examples: granite, tacos, bowl of cereal, big Mac, Italian salad dressing, concrete, crunchy peanut butter, sandwich….

18. Homogeneous Mixture Homogeneous mixture Well-mixed, appears to be the same throughout. Particles are small, not easily recognizable and do not settle when the mixture is allowed to stand. Examples: air, milk, glass, stainless steel, kool aid…

19. Colloids Colloids Homogeneous mixtures where the particles are mixed together but not dissolved. The particles in a colloid are relatively large in size and are kept permanently suspended. Colloids do separate on standing as do many heterogeneous mixtures. Examples: milk, whipped cream, toothpaste, suntan lotion…

20. Solution Solution Type of homogeneous mixture formed when one substance is dissolved in another. “Best mixed” of all mixtures. Particles are evenly spread out. Examples: soda pop, lemonade, kool aid, tea Solute – substance that is dissolved Solvent – substance that does the dissolving

21. Properties of solutions See chart on word document Solutions can exist in any of the three phases: solid, liquid or gas. Property of solution is that particles are evenly spread out (dissolved)

22. Solubility Solubility Amount of solute that can be completely dissolved in a given amount of solvent at a specific temperature. How can you increase the solubility of a substance? Increase temp-increase solubility (add heat energy) Increase agitation-increase solubility Decrease temp-decrease solubility

23. Soluble/Insoluble A substance that dissolves in another substance is soluble in that substance. (sugar is soluble in water) Insoluble does not dissolve (sand in water)

24. Alloys Alloys Metal solutions Solids dissolved in solids. Gold jewelry is a solid solution of Au and Cu Brass is an alloy of Cu and Zn Sterling silver is an alloy of Ag and Cu Stainless steel is an alloy Cr and Fe

25. Pure Substances Pure substances Matter that cannot be separated by physical means (elements and compounds) Element Substance that contains only 1 type of atom Examples: H, He, O, B … anything from periodic table

26. Compounds Compound Substance formed when different types of atoms bond with one another Composed of 2 or more atoms bonded together Examples: NaCl, C12H22O11, NaOH, AgCl

27. Compounds differ Chemical compounds are uniquely different from the elements that make them up. Sodium and chloride are extremely toxic by themselves, however sodium chloride is necessary for good health.

28. Molecule Molecule 2 or more atoms bonded together. Smallest particle of a compound that has all the properties of that compound. Examples: H2O NaCl Sketch molecules on board

29. Elements, compounds, mixtures See word document for chart Sketch matter flow chart on board (This is on study guide to save copy time) Classify list from word document (do orally)

30. Separate mixtures Explain how you could use physical properties to separate the following mixtures: Sand-salt Oil-water Salt-water Rubbing alcohol-water Sawdust-sand Gold-sand Iron filings-sulfur

31. Atoms Atom Smallest particle of an element that has all the physical and chemical properties of that element Basic building block of all matter Atoms are mostly empty space (analogies)

32. Chemical Symbol Chemical Symbol Shorthand way to represent an element Single letter or first letter is always capitalized Second letter is always lower case As, Fe, Se, He, Ar, ….

33. Chemical Formula Elemental (Chemical) formula Combination of chemical symbols to represent a substance’s identity Atomic symbol along with a numerical subscript to indicate the number of atoms grouped together

34. Chemical formulas O2 - 2 - O atoms O3 - 3 – O atoms S8 - 8 – S atoms 4 O2 - 4 – O2 molecules - 8 – O atoms NaCl, Fe2O3, KCl

35. Applied Chemical Formulas List the element and the number of atoms for each element NaHCO3 C12H22O11 3 H2SO4 5 CaCO3

36. Remember Remember—chemical compounds are uniquely different from the elements from which they are made. Na+ - toxic – explosive in water Cl- - toxic – green gas, death in less than 1.5 seconds NaCl – table salt—sodium chloride—essential for good health

37. The “real” world In nature, it is rare that elements or compounds are found in a purified state. We find them “mixed together” in mixtures, which can be separated by differences in physical properties.

38. Chemical Equation Chemical Equation Description of a chemical reaction using symbols and formulas 2 H2 + O2 2 H2O Draw molecules on board

39. Chemical Reaction Chemical Reaction Atoms are re-arranged and a new substance with different properties is formed Reactants Products Yield, produce

40. Chemical reaction Existing bonds are broken, atoms are re-arranged, new bonds are formed to produce new substances Energy is either absorbed or released

41. Exothermic Reaction Exothermic chemical reaction (HOT) Exo “out of” thermic “heat” Heat energy is released

42. Endothermic Reaction Endothermic chemical reaction (COLD) Endo “into” thermic “heat” Heat energy is absorbed (Need to add heat energy to keep reaction going)

43. Catalyst Catalyst Speeds up a chemical reaction without being permanently being changed itself

44. Law of Conservation of mass Law of Conservation of Mass (Matter) Matter is neither created or destroyed in a chemical reaction. Atoms are re-arranged, however, the same atoms and number of atoms remain on both sides of the reaction.

45. Balancing equations Balance chemical equations Write equations on board Prepare for unit quiz