1. Two broad categories of matter: 1. Mixtures 2. Substances
2. Mixtures are physical combinations. Can be separated physically.
3. Homogeneous mixtures uniform composition: air, aqueous solutions, metal alloys
4. Heterogeneous mixtures have visible differences.
5. Substances are either elements or compounds. All substances are homogeneous.
6. Elements can’t be decomposed chemically.
7. Compounds are chemical combinations of at least two different elements in specific ratios. Can be decomposed chemically.
8. Exothermic processes release energy. In chemical reaction form energy appears as a product.
9. Endothermic processes absorb energy. Energy is a reactant.
10. Bond breaking is endothermic.
11. Bond formation is exothermic.
12. Unit of energy is the Joule. 1 kilojoule = 1,000 joules
13. Average Kinetic Energy = Temperature
14. Potential energy is stored in chemical bonds.
15. Fixed points on a thermometer are 0 degrees Celsius and 100 degrees Celsius.
16. K= C +273
17. Phases are solid, liquid, gas.
18. Solidàliquidàgas is an endothermic process.
19. Gas à liquidà solid is an exothermic process.
20. Kinetic energy does not change during a phase change. Potential energy does.
21. Sublimation is solidàgas: Deposition is gasà solid: only I2 and CO2
22. Gases are spread out, no definite molecular pattern, take the volume of the container.
23. As Pressure increases gas volume decreases
24. As Temperature increases gas volume increases.
25. Combined gas law is on Table T always use K for temp.
26. PV=k: pressure x volume = a constant (in a closed container)
27. STP is equal to 760 torr, 1 atm, and 0 celsius, 273 K.
28. Absolute Zero = O K: no kinetic energy.
29. Kinetic Molecular Theory of Gases.
a. Ideal gases have no particle volume
b. Ideal gases have no IMF’s
c. Particles are in continuous straight-line motion.
30. Real gases deviate from ideal gases because they have particle volume and they have IMF’s. Light gases are more ideal than heavy gases.
31. Real Gases are most ideal under conditions of low pressure and High temp.
32. Equal volumes of gases have equal numbers of particles: Avogadro’s hypothesis
33. Liquids have definite volume but not shape.
34. Vapor pressure is the pressure created by the portion of liquid that has “vaporized”. Vapor pressure increases with Temp.
35. The weaker the IMF’ the higher the vapor pressure at any given Temp. Table H.
36. Boiling pt. The temp when vapor pressure = atmospheric pressure, normal b.p. occurs at standard pressure
37. Heat of vaporization the energy to turn a given sample of a liquid to a gas, or condense a gas into a liquid.
38. Solids have a crystal structure. Definite shape and volume.
39. Melting point: Temperature at which a solid becomes a liquid.
40. Heat of Fusion the amount of energy to freeze or melt a given mass of a substance.
41. To find out how much energy is absorbed or released during temperature changes use q = mCdeltaT. C is specific heat of a substance. For water C=4.18 J/g
42. During a phase change there is phase equilibrium between two phases.
a. solid becomes liquid at the same rate that liquid becomes solid
b. liquid becomes gas at the same rate that gas becomes liquid
43. Be able to draw the 3 phases of matter:
44. Here is a heating curve. Note that this is for water so b.p. and m.p. will change for other substances. Also this curve can be reversed to make it a cooling curve. This curve is endothermic. Phase changes (equilibrium) are the flat lines.