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

2. 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

3. 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

5. 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)

6. 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

7. 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 +

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

9. 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

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

11. 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)

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

13. 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+