legislating risk risk based laws – fda balancing laws –clean air act –safe drinking water act...
Post on 22-Dec-2015
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Legislating Risk
• Risk based laws – FDA
• Balancing laws– Clean Air Act– Safe Drinking Water Act
• Technology based laws– Proposition 65 in California
Controversy
• Animal experiments– Ethical?– Depend on how done?
• Cold fusion
• Greenhouse effect
• Cholesterol
Chemical Lingo
Elements
• Fundamental types of matter– Cannot be separated anymore
• All other substances are composed of 2 or more elements
• Most of the substances you know are not elements– Common elements
• Gold (24K)• Aluminum (foil)• Carbon (charcoal, diamonds, pencil “lead”)
Metals
• Shiny: Reflect light
• Opaque: Light doesn’t pass through
• Malleable: Can be hammered into shape
• Ductile: Can be drawn into wire
• Conductive: Both heat and electricity
• Most elements are metals– All are solids except mercury (Hg)
Nonmetals
• Are not malleable, ductile, or good conductors
• Solids, liquids, and gases
Symbols
• Each element has its own symbol– One or two characters– First character always capitalized– Second character never capitalized
• CO not the same as Co
• See table inside back cover
Atoms
• Smallest particle of an element with properties of the element
• Limit of chemical subdivision
• John Dalton – Theory of atoms– All matter made of atoms – 115 types →
elements– All atoms of same type are similar but
different from other types
Atoms
• John Dalton – Theory of atoms (cont.)– Relative number and arrangement of
atoms→identity– Chemical change: union, separation, or
rearrangement of atoms– Atoms are indestructible during chemical
changes• Approx. 245,000,000 atoms/inch• Have seen atoms with electron microscopes
Compound
• Chemical combination of two or more elements.– Can’t be physically separated
• Can be broken down into constituent elements using chemical means.
• Has a definite, constant, elemental composition• Has one set of properties under a given set of
conditions.• Has different properties than those of it’s
constituent elements
Mixtures
• Physical combination of two or more substances.
• Components can be separated using physical means.
• Variable compositions possible
• Variable properties as composition varies
• Heterogeneous and homogeneous
Homogeneous Mixtures
• Components are dispersed on a molecular scale
• Solutions
• Appear to be pure substances
• One set of properties for each mixture
Heterogeneous Mixtures
• Components are dispersed on a larger than molecular scale
• Do not appear to be pure substances– You can see phase boundaries
• Different properties for different parts of the mixture
Heterogeneous Mixtures
• Components are dispersed on a larger than molecular scale
• Do not appear to be pure substances– You can see phase boundaries
• Different properties for different parts of the mixture
• Sometimes may appear as a pure substance– Colloids
H2 – C1
• 2, 3, 5 - 7, 9, 10, 12, 35, 39 - 41, 43, 54
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