Warm-Up1. What 2 elements besides H and N

make up the bulk of living matter?2. 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?

3. What kinds of bonds form between water molecules?

Chapter 2Part 2: Reactions & Inorganic Compounds

Chemical Reactions• Reactants Products

• Eg. 6CO2 + 6H2O C6H12O6 + O2

• Some reactions are reversible:• Eg. 3H2 + N2 2NH3

• 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 Patterns of Chemical Reactions1.1. SynthesisSynthesis = combining atoms/molecules to

form larger, more complex molecule A + B AB Anabolic reactions

2.2. DecompositionDecomposition = breaking apart molecules AB A + B Catabolic reactions

3.3. Exchange Reaction Exchange Reaction = bonds made/broken to exchange parts

AB + C AC + B AB + CD AD + CB

Factors influencing rate of reaction:Temperature: temp, rateConcentration: reactants, rate (as reactants ,

rate will )Particle size: small particles move fasterCatalysts: increase rate of reactions (enzymes)

Two classes of chemicals:1.1. Inorganic compoundsInorganic compounds: no carbon

Small, simpleWater, salts, acids, bases

2.2. Organic compoundsOrganic compounds: contain carbonUsually large, complexCarbs, lipids, proteins, nucleic acids

WaterPolar moleculePolar molecule = shares

electrons (e-), but not shared equally

Electrons spend more time around oxygen (very electronegative)

OxygenOxygen end of H2O slightly --HydrogenHydrogen end of H2O slightly

++

Hydrogen bonds in waterAttraction between (+) end of polar molecule

with the (-) end of another polar molecule

Properties of Water1.1. High heat capacityHigh heat capacity: absorb/release heat;

maintain constant temps

2.2. High heat of vaporizationHigh heat of vaporization: liquid gas; evaporative cooling

3.3. Polar solventPolar solvent: dissolve substances; universal solvent

4.4. ReactivityReactivity: involved in many chemical reactions

5.5. CushioningCushioning: protect, cushion organs

SaltsIonic compoundsDissolve in H2OElectrolytes –

conduct electrical current in solution

Common salts in body: NaCl, CaCO3, KCl, calcium phosphate (bones)

Acids & BasesAcidAcid: release hydrogen (H+) ions (proton donor)

HCl H+ + Cl-

Sour tasteEg. acetic acid, carbonic acid

BaseBase: take up H+ ions (proton acceptor)NaOH Na- + OH-

Bitter taste, feel slipperyEg. bicarbonate ion (HCO3

-), ammonia (NH3)

pH ScaleAcids: pH < 7Neutral pH = 7Bases: pH >7

BuffersMaintain homeostasis by resisting changes in

pH of body fluidsBlood pH: 7.35 – 7.45Release H+ ions when pH rises; bind H+ ions

when pH dropsWeak acids or basesMajor bufferMajor buffer: carbonic acid – bicarbonate

systemH2CO3 (carbonic acid) HCO3

- (bicarbonate) + H+