1. Warm-Up
What 2 elements besides H and N make up the bulk of living matter?
An element has a mass of 207 and has 125 neutrons in its nucleus. How many protons and electrons does it have and where are they located?
What kinds of bonds form between water molecules?

2. Chapter 2 Part 2: Reactions & Inorganic Compounds
Chemistry Comes Alive
Chapter 2
Part 2: Reactions & Inorganic Compounds

3. Chemical Reactions Reactants  Products Some reactions are reversible:
Eg. 6CO2 + 6H2O  C6H12O6 + O2
Some reactions are reversible:
Eg. 3H2 + N NH3
Chemical equilibrium: point at which forward and reverse reactions offset one another exactly
Reactions still occurring, but no net change in concentrations of reactants/products

4. 3 Patterns of Chemical Reactions
Synthesis = combining atoms/molecules to form larger, more complex molecule
A + B  AB
Anabolic reactions
Decomposition = breaking apart molecules
AB  A + B
Catabolic reactions
Exchange Reaction = bonds made/broken to exchange parts
AB + C  AC + B
AB + CD  AD + CB

6. Factors influencing rate of reaction:
Temperature: temp, rate
Concentration: reactants, rate (as reactants , rate will )
Particle size: small particles move faster
Catalysts: increase rate of reactions (enzymes)

7. Two classes of chemicals:
Inorganic compounds: no carbon
Small, simple
Water, salts, acids, bases
Organic compounds: contain carbon
Usually large, complex
Carbs, lipids, proteins, nucleic acids

8. Water Polar molecule = shares electrons (e-), but not shared equally
Electrons spend more time around oxygen (very electronegative)
Oxygen end of H2O slightly -
Hydrogen end of H2O slightly +

9. Hydrogen bonds in water
Attraction between (+) end of polar molecule with the (-) end of another polar molecule

10. Properties of Water
High heat capacity: absorb/release heat; maintain constant temps
High heat of vaporization: liquid  gas; evaporative cooling
Polar solvent: dissolve substances; universal solvent
Reactivity: involved in many chemical reactions
Cushioning: protect, cushion organs

11. Salts Ionic compounds Dissolve in H2O
Electrolytes – conduct electrical current in solution
Common salts in body: NaCl, CaCO3, KCl, calcium phosphate (bones)

12. Acids & Bases Acid: release hydrogen (H+) ions (proton donor)
HCl  H+ + Cl-
Sour taste
Eg. acetic acid, carbonic acid
Base: take up H+ ions (proton acceptor)
NaOH  Na- + OH-
Bitter taste, feel slippery
Eg. bicarbonate ion (HCO3-), ammonia (NH3)

13. pH Scale
Acids: pH < 7
Neutral pH = 7
Bases: pH >7

14. Buffers Maintain homeostasis by resisting changes in pH of body fluids
Blood pH: 7.35 – 7.45
Release H+ ions when pH rises; bind H+ ions when pH drops
Weak acids or bases
Major buffer: carbonic acid – bicarbonate system
H2CO3 (carbonic acid)  HCO3- (bicarbonate) + H+