Download Chem and Water Review Guide

HONORS BIOLOGY
Chapter 2 Quiz Review
Name ____________
Chemistry and Radioisotopes
These are topics and vocabulary terms covered in this chapter which may appear on the chapter test.
Also see pp. 18-23, 30-31 in text for more review.
Elements, Atoms, and Molecules
 Why is chemistry important to biology?
 Elements (all same atoms); compounds (different elements, in a ratio)
 Major elements in biology – C, H, O, N,
 Some minor elements – ex. Cl, Na, P, S – cell parts and chem. reactions
 Some trace elements – iodine- thyroid; iron– oxygen in blood; fluorine-teeth
Atomic Structure
 Matter, Atomic Theory, Law of Conservation
 Nucleus – particles, charges, most mass of atom
 Electrons – electron cloud, charge, most volume of atom
 Energy levels, valence electrons determine chemical activity
 Octet Rule- to fill valence 2-8-8, atom then stable
 Atomic number, mass number (protons + neutrons)
 Isotopes and average atomic mass – same element, different # neutrons
Radioisotopes
 Unstable – decay to different element, but now stable
 Half-life, be able to calculate amount remaining or age of fossil
 Uses: date fossils – use carbon 14
o research “tracers” – use carbon and other isotopes
o medical tests - PET scans, iodine goes to thyroid, technetium to bone
o radiation therapy - internal pellets or external (use cobalt)
o nuclear energy – use uranium; kill bacteria
Compounds and chemical bonding
 ions: electrons gained or lost  (+) and (-) charges
 ionic bonding - opposite charges attract each other
o forms a crystal, dissociates in water individual ions
 Covalent bonding – form molecules, share valence electron pair
o Bonds do not break in water but molecules separate
 Chemical formula, structural formula
 Chemical Reactions – reactants and products; same atoms, different combinations
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HONORS BIOLOGY
Chapter 2 Quiz Review
Water and its Properties
Name ____________
These are topics and vocabulary terms covered in Chapter 2 which may appear on the chapter test or
quizzes. Also see pp. 24-31 in text for more review.
The Water Molecule
 Why is water necessary for life?
 Polar covalent bonds – electrons shared unevenly around molecule
 Water molecule – more electrons on oxygen end (-)
 Shape is bent, has (+) and (-) poles
 Hydrogen bonds – H on one molecule  oxygen on another
Properties of water
What are they? Why are they important in living things?
 Cohesion – hydrogen bonds hold water molecules together
o Surface tension – acts like a membrane for cells
o High specific heat – stores heat without changing temp
o Temperature moderation – keeps temp stable in organisms,
 constant ocean temp, slow season changes, mild coastal climate
o High heat of vaporization – surface water molecules take heat away
 Evaporative cooling
o Why ice floats –less dense than liquid water, molecules farther apart
 Ice insulates ponds, so water below stays liquid
o Capillary action/capillarity – water climbs up narrow tube, small spaces
o Transpiration in plants – water climbs against gravity through pull from
evaporation on leaves; roots stem leaves air
 Adhesion – water forms hydrogen bonds to other substances
o Universal solvent – polar and ionic, but not nonpolar
o Dissolve in water – ions dissociate; molecules stay intact
o Capillary action – uses both cohesion and adhesion
 Blood vessels in animals, veins in plants
Solutions and Mixtures
 Solvent and solute – solvent= main part of a mixture
 Aqueous solution – solvent is water; fluids in all living things
 Suspension – too big to dissolve; ex. Blood - cells in watery fluid
Acids and bases
 pH : [H+] ion concentration
 acid – higher H+, pH below 7; base- higher OH- (lower H+), pH above 7
 neutralization reaction: acid + base  salt (ionic) + water
 buffers – weak acid or base, minimizes pH change
 in humans: mostly pH 7; stomach –acid, pancreas – base, intestine - neutral
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