1. Matter Chapter 2

2. Chemistry  The study of matter and how it changes  Matter = has mass and takes up space  Simplest form of matter = Atoms  Different types of atoms = elements. (they cannot be broken down)

3. Compounds  Atoms of more than one element bound together.  Ex: H 2 O, C 6 H 12 O 6, NaCl, HCl  Molecule = smallest unit that exhibits all the properties of that substance  Ex: H 2 O, C 6 H 12 O 6

4. Chemical Formulas  Chem symbols and numbers tell us how many of each element is in a compound  Example: The chem formula for table sugar is C 12 H 22 O 11. Each molecule contains 12 carbon atoms, 22 hydrogen atoms, and 11 oxygen atoms.

5. Types of Matter  Pure Substance = matter with fixed composition and definite properties  Mixture = Combination of more than one pure substance.  Ex: Grape Juice is a mixture of pure substances such as water, sugar, vitamins, etc…

6. Types of Pure Substances  Elements – listed on the Periodic Table  Compounds – Combination of elements

7. Types of Mixtures  Heterogeneous – subs are NOT uniformly mixed  Example: mixture of flour and water  Homogeneous – subs are evenly mixed (looks the same throughout)  AKA Solution  Example: mixture of salt and water – the salt dissolves in the water

8. Liquid Mixtures  Miscible – liquids are able to dissolve into each other  Homogeneous mixture of liquids  Gasoline = homo. mixture of 100 compounds  Immiscible – liquids are NOT able to dissolve into one another  Heterogeneous mixture of liquids  Oil and water will not mix

9. Buoyancy  The force with which a more dense fluid pushes a less dense subs up.  Ice is less dense than water.

10. Archimedes’ Principle 4the buoyant force on an object equals the weight of the fluid displaced by the object

11. Bernoulli’s Principle 4As the velocity of a fluid increases, the pressure exerted by the fluid decreases 4Explains why planes can fly

12. Mixtures with Gases  Many gases form mixtures with other gases or liquids  Ex: Air – homo. mixture of gases  Ex: Soda – homo. mixture of gas and liquid  Ex: Foam – mixture of gas and liquid

13. Kinetic Theory  All matter is made up of atoms or molecules.  The atoms/molecules are always in motion.  More massive atoms/molecules move slower.

14. States of Matter  Solid  Liquid  Gas  Plasma – most common state in the universe  Very fast moving charged particles  Makes up stars

15. Solids  Definite volume and shape – “Rigid”  Atoms are held together with strong forces  Particles vibrate in fixed position

16. Liquids  Definite volume, indefinite shape  Atoms slide past one another  Viscosity = property that describes the resistance of a fluid to flow

17. Gases  Indefinite shape and volume  Atoms not very attracted to each other  Free motion  Exert pressure

18. Energy  Ability to cause changes in the states of matter (phase changes)  Evaporation  Liquid  Gas  Energy is absorbed (by a liquid causing atoms to move faster until they break away from the liquid surface to form a gas.)

19. More Phase Changes  Condensation  Gas  Liquid  Releases energy (energy is given from the gas to the surroundings)  Sublimation  Solid  Gas  Energy is absorbed  Ex: CO 2 (s)  CO 2 (g) Dry Ice

20.  Insert picture from p. 382 chemistry book

21. Phase Change Diagrams  Show the changes of state for any subs.  Show the temperatures where the phase change occurs  Is more energy used to convert ice to water or water to steam?

22.  Insert phase diagram on p. 49

23. Heat of Fusion  Amount of heat required to melt a solid at its melting point  Different for every subs.

24. Heat of Vaporization  Amount of heat needed to change a liquid into a gas at its boiling point  Also different for every subs.

25. State Changes  No change in the composition or mass of the atoms.  Law of Conservation of Energy  Energy cannot be created or destroyed  Law of Conservation of Mass  Mass cannot be created or destroyed

26. Properties of Gases  Thermal Expansion = gas molecules become farther apart as temp increases  Pressure = Force exerted per unit area of a surface  Unit: atmospheres (atm)  Pressure around us comes from air molecules

27. Boyle’s Law  Relates pressure (P) and volume (V)  As P increases, V decreases  P 1 V 1 = P 2 V 2  Inverse relationship

28. Charles’s Law  Relates V and temperature (T)  As T increases, V increases  V 1 = V 2 T 1 T 2  Direct relationship

29. Combined Gas Law  Includes P, V, and T  P 1 V 1 = P 2 V 2 T 1 T 2

30. Chemical Properties  Methods that a subs can use to transform into a new subs with different properties  Reactivity = ability of one subs to combine with another subs  Ex: flammability, corrosiveness, rusting, explosiveness,

31. Physical Properties  Characteristic of a subs that can be observed without changing the subs  Ex: Melting point (s  l) Boiling point (l  g)

32. Density  Physical property  The amount of mass in a certain volume  D = m/V  Units = g/mL or g/cm 3

33. Chemical Changes  Change that occurs to form a new subs. (product has a different composition.)  Ex: Digesting food, steel rusting, food burning, gasoline combusting, milk souring

34. Signs a Chemical Change Occurred  Odor  Color change  Gas produced (bubbles)  Solid produced  Temperature change (hot or cold)

35. Physical Changes  Change that does NOT alter the composition of the subs.  Melting chocolate, freezing water, tearing paper, chopping food, dissolving sugar  Dissolving = water molecules surround the other molecules and spread them out evenly.