1. What is Chemistry? It is the study of the composition, structure, and properties of matter and the changes it undergoes A Chemical: is any substance that has definite composition - it is always made up of the same stuff.

2. Matter Is anything that has mass and takes up space. Fundamental building blocks of matter: Atoms: the smallest unit of an element that maintains the properties of that element. –Element: a pure substance made up of only one kind of atom. (oxygen, hydrogen, carbon) –Compound: is a substance that is made from the atoms of two or more elements that are chemically bonded Many compounds consist of molecules –Mixtures: combinations of elements and compounds Mass is a measurement of the quantity of matter Elements, compounds, and mixture are kinds of matter

3. Properties Extensive Properties: depend on the amount of matter that is present. –Such as: volume, mass, and amount of energy Intensive Properties: do NOT depend on the amount of matter present. –Such as: boiling point, density, and ability to conduct electricity or heat.

4. Physical Properties A characteristic that can be observed or measured without changing the identity of the substance. Basically, it describes the substance itself, rather than how it can change into other substance. –Example: Melting Point and Boiling Point properties of an element or compound that can be observed without a chemical reaction of the substance. A substance's color and density are physical properties

5. Physical Changes So what is a physical change? –A change that does not involve a change in the identity of a substance –Example: cutting, melting, boiling A change of state is a physical change of a substance from one state to the other. The substances are not altered chemically, but merely changed to another phase (i.e. gas, liquid, solid) or separated or combined

6. The States of Matter SOLID: ordered arrangement; particles are packed close together. Solids have definite shape and definite volume. LIQUID: disorder; particles or clusters of particles are free to move relative to each other. Liquid has definite volume, but not definite shape. GAS: total disorder; empty space; particles have complete freedom of motion. Gas has neither definite shape or volume.

7. Solid Particles have the least amount of energy. Their motion is so weak that the particle cannot push other particles out of the way. Because of this the particles of a solid are packed close together.

8. Liquid Particles have enough energy to push other particles out of the way. When the particles of a liquid bump into each other, they push the particles farther apart and move past them. This causes the liquid to"flow.”

9. Gas Particles have a high amount of energy. The particles collide with enough force to push the particles so far apart that they escape the attraction of the surrounding particles. Gas particles have the most energy of any "regular" phase of matter.

10. Plasma Particles have extremely large amounts of energy. The collisions in a plasma are so violent that electrons are knocked away from their atoms. So atoms lose their electrons.

11. © UC Regents http://ds9.ssl.berkeley.edu/LWS_GEMS/2/part2.htm

12. Phase Changes Vaporization: Liquid Gas (water boiling) Condensation: Gas Liquid (dew on grass in morning) Freezing: Liquid Solid (ice cubes) Sublimation: Solid Gas (dry ice) Deposition: Gas Solid (frost in winter) Melting: Solid Liquid (candle)

13. Phase Changes Condensation Evaporation Melting Freezing Sublimation Deposition GAS LIQUID SOLID

14. The phase diagram is graph of pressure vs. temperature that shows conditions under which the phases of a substance exits: http://itl.chem.ufl.edu/4411/2041/lec_f.html

15. Phase Diagram for Water http://www.chem.uidaho.edu/~honors/phases.html

16. Triple Point : The lower point is called the "triple point" and is the unique combination of temperature and pressure at which all three phases exist simultaneously. Critical Point: is point along the boiling point curve where the line between the liquid and gaseous phases disappears. At temperatures higher than this point there is only a single phase which is a very dense gas, or frequently called a critical fluid.

17. Heating/Cooling Curve Heat of Vaporization Heat of Fusion/Crystallization Energy is added as Heat

18. Chemical Properties A substance’s ability to undergo changes that transform it into different substances For example: When charcoal (carbon) burns, it combines with oxygen in the air and forms carbon dioxide gas. Chemical Changes A change where one or more substances are converted into a different substance ( chemical reaction) - display different physical and chemical properties after the change Reactants: The substances that react in a chemical change. Products: the substances that are formed in a chemical reaction

19. Chemical Changes In a chemical change, the identities of the substance changes –mercury(II)oxide mercury + oxygen –Substance to the left is the reactant –Substances to the right are products

20. Signs of a Chemical Change 1) Color Change: red iodine with a potato = blue 2) Precipitation: when a solid forms from the combination of at least two liquids (solutions) 3) Energy Changes: heat or light can be absorbed or released during a reaction - matches: released -ice cube: absorbed 4) Odor Change: when food spoils 5) Gas production/release: car exhaust or calcium metal in water give off hydrogen gas

21. Pure substance: has a fixed composition Every sample of a pure substance has – exactly the same characteristic properties – exactly the same composition Pure substances are either compounds or elements. Mixture: is a blend of two or more kinds of matter, each of which retains its own identity and properties. Variable in Composition The parts of a mixture are physically mixed and can usually be separated. The properties of a mixture is usually a combination of the properties of its components.

22. Mixtures Homogeneous: mixtures that are uniform in composition. –Have the same proportions of components throughout. –Also called solutions, such as salt water Heterogeneous: mixtures that are not uniform throughout. –Clay and water: clay sinks to the bottom

23. Matter MixturePure substance HomogeneousHeterogeneousElementCompound Two or more elements Same Throughout Different Throughout Black CoffeeVegetable Soup Na Single Substance Na 2 O

24. Separation of Mixtures Distillation: heating a mixture to boil water out and then recollecting the water, by cooling the steam. The water changes from liquid, to gas and then back to liquid. Filtration: using mesh or filter paper to catch larger particles and allow liquids to pass through Centrifuge: using high speed spinning to separate based off of density Chromatography: uses solubility to separate material based off of size and attraction.

26. Changes in Matter and Energy Matter cannot be created or destroyed. But it can be changed and when it does, that is how we get energy! Energy - capacity to do work or produce heat –Energy is always involved in physical and chemical changes. –Energy can take several forms: Heat, light, (sound, chemical, electrical) –Measured in calories, Calories (kcal), and joules

27. Law of Conservation of Energy: energy can be absorbed or released, but it cannot be created or destroyed through ordinary chemical reactions. (exception: nuclear energy, where energy is created from mass moving at high speeds) Energy can be transferred. –It flows from high concentration to low concentration. –Since energy can’t be destroyed it must go from one type of energy to another!

28. Conservation of Energy KE changes to PE PE changes to KE

29. Kinetic and Potential Energy Kinetic energy: is the energy of motion. An object which has motion - whether it be vertical or horizontal motion - has kinetic energy. When you drop a ball from a great height Potential Energy: energy of Position Stored energy (enthalpy) The energy that could be used but is not yet being used (the ball before you drop it) Objects with the capacity to do work but not active now have PE.

30. Since energy is constant and cannot be created or destroyed …. Total Energy = KE + PE Temperature: a measurement of average kinetic energy of all particles within and object. (slow movement, low temperature) There are times during phase changes when temperature does not change, but stays constant while the energy works to change the phase (ie: the heating curve of water)

31. Heating/Cooling Curve Heat of Vaporization Heat of Fusion Energy is added as Heat

32. Exothermic –energy is released by the substance into the surroundings –less PE, more KE, so temperature rises –Ex: a match burning Endothermic – energy is absorbed by the substance from the surroundings –more PE, less KE, so temperature drops –Ex: water freezing

33. Energy Calorie (cal): the amount of energy (heat) required to raise the temperature of one gram of water by one Celcius degree Standard unit for energy is the joule (J) 1 cal = 4.184 J 60.1 cal x 4.184 J = 251 J 1 cal Specific Heat (s) : amount of energy required to change the temperature of one gram of a substance 1 o C Varies from one substance to another Heat always travels from high concentration to low concentration!! Heat lost = Heat gained

34. Water has a specific heat = 1 cal/g o C or 4.184 J/g o C –Water has the second highest specific heat capacity of all known substances. So it requires high amounts of heat energy to raise water temperature. –water also has a high energy/heat requirement for evaporation S IRON = 0.449 J/g o C –Which would heat up faster, 5.00 grams of iron or 5.00 grams of water? – Which would cool down faster, 5.00 grams of iron or 5.00 grams of water? – Which is a better thermal conductor? – Which is a better insulator?

35. Q = s x m x  T Q = energy (heat) required (J) or (cal) s = specific heat capacity (J/g o C) or (cal/g o C) m = mass of the sample in grams  T = change in temperature in o C A 2.8 g sample of a pure metal requires 10.1 J of energy to change its temperature from 21 o C to 36 o C. What is the specific heat of the metal? s = Q = 10.1 J = 0.24 J/g o C m x  T (2.8 g x 15 o C)