1. QotD: Where does the energy required to run your car come from? How does it run your car? Where does the energy required to run you come from? How does it work? 1

2. MATTER AND ENERGY Before we discuss metabolism and cellular respiration, we need to understand the nature of matter and energy. 2

3. Story Time A Matter of Explosions pgs. 292-293 3

4. MATTER: The material “stuff” of the universe; has mass and takes up space. Forms of Matter Elements (all atoms of one kind) Can you name one? Compounds (atoms of two or more kinds bonded) Can you name one? 4

5. Atoms basic units of matter 5

6. 6 Atomic Structure (Bohr model) Nucleus of protons + neutrons Number of protons = atomic number thus kind of atom/element, number of positive charges. Number of neutrons variable isotope(s) Cloud of electrons with negative charges. Normally # electrons = # protons.

7. Elements 118 on Periodic Table Arranged by number/atomic mass and chemical properties. http://www.webelements.com/ Song by Tom Lehrer: http://www.privatehand.com/flash/eleme nts.html http://www.webelements.com/ http://www.privatehand.com/flash/eleme nts.html 27 Jan. 2009Matter-&-Energy.ppt 7

8. Bonding atoms to make molecules Chemical reactions 8

9. 9 Ionic bond Atoms lose/gain electrons, become charged ions Example: sodium + chlorine = sodium chloride Na + Cl  Na + + Cl - Ionic bonds can usually be dissolved with water

10. 10 Covalent bond atoms share electron pairs examples: carbon + hydrogen (4)  CH 4 (methane) hydrogen + hydrogen  H 2 molecule 2 H 2 + O 2  2 H 2 O (water)

11. Game Time Red Rover Ionic Bonds Covalent Bonds 11

12. Carbon Forms covalently bonded chains “Backbone” of huge variety of organic chemicals Petroleum Propane Ethanol Glucose, a simple sugar 12

13. MATTER Can change composition by chemical reaction Can change physical state Solid (ice) Liquid (water) Gas (water vapor) 27 Jan. 2009Matter-&-Energy.ppt 13

14. MATTER Can be mixed or dissolved with other matter Soil + water  mud (mixture) Sugar + water  syrup (solution) Can change crystalline form snowflake vs. ice solid ice on lake vs. “honeycomb” ice limestone vs. mother of pearl 27 Jan. 2009Matter-&-Energy.ppt 14

15. LAW of CONSERVATION of MATTER  MASS before = MASS after in all these changes, no loss or gain of matter  There is no AWAY. What we “throw away” is still here somewhere.  { Exception: Nuclear fission or fusion—mass converted to energy in nuclear power, atomic bomb, core of sun. } 15

16. ENERGY Work, or capacity/potential to do work Work = mass moving (moved) kinetic energy heat light electricity chemical potential 16

17. ENERGY Can be converted from one form to another. Thermonuclear e. in sun  light  (photosynthesis)  chemical potential in organic chemicals (coal)  heat (burning)  steam pressure  kinetic  electrical  light (bulb/tube) and heat. Can rearrange and release heat 17

18. Electromagnetic spectrum 18

19. Electromagnetic radiation Nonionizing Visible & longer wavelengths Lower energy, won’t knock electrons off molecules Ionizing Ultraviolet & shorter wavelengths High energy photons do knock off electrons Create ions 27 Jan. 2009Matter-&-Energy.ppt 19

20. First Law of Thermodynamics Energy may be converted but is neither created nor destroyed. Energy input = energy output Concentrated, high quality energy = work done + heat dissipated 20

21. Second Law of Thermodynamics In converting one form of energy to another, some is lost or degraded (as heat). No mechanism can be 100% efficient. You can’t break even. 21

22. Second Law of Thermodynamics Maintenance of complex, dynamic system requires energy input. Then, energy conversions lose energy to universe. Without more energy input, disorder (“entropy”) increases. 27 Jan. 2009Matter-&-Energy.ppt 22

23. Application: Combustion Gasoline to power cars 2C8H18 + 25O2 Energy + 16CO2 + 18H2O Sugar to power organisms C6H12O6 + 6O2 Energy (ATP) + 6CO2 + 6H2O 23