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Compound
- is a substance consisting of two or more different elements in a fixed ratio
- -sodium chloride
- -table salt
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Trace elements
- -are essential but are only needed in minimum quantities
- -iron you can become anemic
- -iodine prevents production of thyroid hormones, resulting in goiter.
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Atom
- -is the smallest unit if matter that still retains the properties of an element.
- -protons +
- -neutrons
- -electrons -
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Atomic Number
the number of protons
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Atomic Mass
- -is approximately equal to its mass number
- -is the sum of the number of protons and neutrons in the nucleus
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isotopes
- -the same number of protons
- -different number of neutrons
- -different isotopes of an element behave identically in chemical reactions
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Electron Shell
- electrons occur
- -2 in the first shell
- -8 in the 2nd shell
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Covalant Bond
- -The strongest kind of bond in which 2 atoms share one or more outer shell electrons
- -ex. molecule
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Ionic Bonds
- -2 ions with opposite charges attract each other
- - when the attraction holds the ions together
- ex. salt
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Hydrogen Bond
- -positevily charged region is always a hydrogen atom,
- -are very weak bonds, can be broken down very easily
- -important for us to stay alive
- ex. water
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Reactants
- -react to produce the product
- h2 and O2
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Cohesion
the tendency of molecules of the same kind to stick together
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adhesion
the tendency of two kinds of molecules to stick together
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Photosynthesis
- -is a chemical reaction that is essential to life on earth
- ex. carbon dioxide (from the air) reacts with water
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Porperties of Water
- Gas: Evaportion
- Liquid: water
- Solid:Ice
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buffer
a substance that minimizes cahnges in pH
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Solution
is a liquid consisting of a uniform mixture of two or more substances
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solvent
the dissolving agent
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solute
the substance that is dissolved
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Acid
- -adds or removes acid
- ex. battery acid, lemon gastric orange juice, vinegar, cola, tomato juice, rain water, human urine, saliva
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Base
- Donates or accepts H+
- ex. sea water, magnesia milk, bleach, oven cleaner
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neutral
ex. pure water, human blood, tears
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pH scale
- -Below 7 is acidic
- -Above 7 is basic
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Acid Precipitation
the acids fall to Earth as "" which is rain, snow, or fog with a pH lower than 5.2
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Ocean Acidification
CO 2 dissolving in seawater lower ocean pH in a process
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