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matter
- anything that occupies space and has mass
- can be seen, smelled, and felt
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energy
the capacity to do work, or to put matter into motion
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kinetic energy
energy in action
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potential energy
- stored energy
- potential energy has the capability to do work but is not presently doing so
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chemical energy
form stored in the bonds of chemical substances
*found in food we eat
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electrical energy
results from movement of charged particles.
- *transmits messages in body.
- *found in flow of electrons along household wiring
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mechanical energy
energy directly involved in moving matter
*when riding a bike, your legs directly provide mechanical energy to move pedals
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radiant energy, or electromagnetic energy
energy that travels in waves
*include visible light, infrared waves, radio waves, UV waves, and xrays
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elements
unique substances that cannot be broken down into simpler substances by ordinary chemical methods
-- all matter is composed of elements
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atoms
building blocks of everything
-smallest particle of an elemental substance that exhibits the properties of that element; composed of protons, neutrons, and electrons
-- comes from the Greek word "indivisible"
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nucleus
- control center of a cell
- contains genetic material
- clusters of nerve cell bodies in CNS
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neutron
- uncharged subatomic particle
- found in atomic nucleus
- neutral, so nucleus is positively charged overall
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protons
- subatomic particle that bears positive electrical charge
- located in atomic nucleus
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electrons
- negatively charged subatomic particle
- orbits the atom's nucleus
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oxygen (O)
- a major component of both organic (carbon-containing) and inorganic (non-carbon-containing) molecules. As a gas, it is needed for the production of cellular energy (ATP)
- 65% body mass
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carbon (C)
- primary component of all organic molecules, which include carbohydrates, lipids (fats), proteins, and nucleic acids
- 18.5% body mass
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hydrogen (H)
- component of all organic molecules. As an ion (proton), it influences pH of all body fluids
- 9.5% body mass
is the simplest atom with just 1 proton and 1 electron and no neutrons
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nitrogen (N)
- component of proteins and nucleic acids (genetic material)
- 3.2% body mass
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calcium (Ca)
- found as a salt in bones and teeth. Its ionic (Ca2+) form is required for muscle contraction, conduction of nerve impulses, and blood clotting
- 1.5% body mass
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phosphorus (P)
- part of calcium phosphate salts in bones and teeth. also present in nucleic acids, and part of ATP
- 1% body mass
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potassium (K)
- its ion (K+) is the major positive ion (cation) in cells. necessary for conduction of nerve impulses and muscle contractions
- .4% body mass
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sulfur (S)
- component of proteins, particularly muscle proteins
- 0.3% body mass
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sodium (Na)
- as an ion (Na+), sodium is the major positive ion found in extracellular fluids. Important for water balance, conduction of nerve impulses, and muscle contraction
- 0.2% body mass
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Chlorine (Cl)
- its ion (chloride, Cl-) is the most abundant negative ion (anion) in extracellular fluids
- 0.2% body mass
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magnesium (Mg)
- present in bone
- important cofactor in a number of metabolic reactions.
- 0.1% body mass
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Iodine (I)
- needed to make functional thyroid hormones
- 0.1% body mass
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iron (Fe)
- component of hemoglobin (which transports oxygen w/in RBCs) and some enzymes
- 0.1% body mass
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atomic number
- equal to the number of protons in its nucleus and is written as a subscript to the left of its atomic symbol.
- the #protons is always equal to the #electrons in an atom, so the atomic # will indirectly tell you the # of electrons in atom as well
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mass number
sum of the masses of its protons and neutrons of an atom
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isotopes
different atomic forms of same element, which vary only in # of neutrons they contain
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atomic weight
- average of the relative weights (mass numbers) of all the isotopes of an element
- atomic weight of element is approx equal to the mass # of its most abundant isotope
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radioisotopes
isotopes that exhibit behavior of radioactivity (atomic decay)
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molecule
combination of two or more atoms held together by chemical bonds
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compound
two or more different kids of atoms bind, forming molecules
*2 hydrogen atoms combine w/1 oxygen atom to form the compound H20
-- compounds are chemically pure and all their molecules are identical
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mixtures
- physical combinations of solutes in a solvent
- mixture components retain their individual properties
*3 basic types: solutions, colloids, suspensions
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mole
a mole of any element or compound is equal to its atomic weight or its molecular weight (sum of atomic weights) measured in grams
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molarity
a way to express the concentration of a solution; moles per liter of solution
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solutions
homogeneous mixtures of components that may be gases, liquids, or solids
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homogeneous
mixture has exactly the same composition or makeup throughout
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solvent
substance present in the greatest amount
*water is the body's chief solvent
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solutes
substances present in smaller amounts
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heterogeneous
composition is dissimilar in different areas of the mixture
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colloids
- aka emulsions
- often appear translucent or milky - do not settle out
- scatter light
- can undergo sol-gel transformations (change reversibly from fluid (sol) to a solid (gel)
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suspension
heterogeneous mixture w/large, often visible solutes that tend to settle out.
*sand and water mixture
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valence shell
atom's outermost energy level or that portion of it containing the electrons that are chemically reactive
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octet rule or rule of eights
- the key to chemical reactivity
- atoms tend to interact in such a way that they have 8 electrons in their valence shell (except for shell 1 which is full when it has 2 electrons)
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ionic bond
chemical bond b/w atoms formed by the transfer of one or more electrons from one atom to the other
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anion
cation
anion - negative charge
cation - positive charge
*both formed whenever electron transfer b/w atoms occurs
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covalent bond
formed when atoms share electron pairs. If electron pairs shared equally, the molecule is nonpolar. If shared unequally, it is polar (a dipole)
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hydrogen bonds
- weak bonds formed b/w one hydrogen atom and another electronegative atom (such as nitrogen or oxygen)
- Bind together different molecules or different parts of same molecule
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exergonic reactions
reactions that release energy - yield products w/less energy
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catalysts
substances that increase the rate of chemical reactions w/o themselves becoming chemically changed or part of the product
*biological catalysts are called enzymes
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