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All Classes
This vocabulary list will be updated to include the most recent terms as
the semester progresses. Words and terms easily found in your textbook will most likely not be included. Keep your eyes open
for links (underlined text) that will help to clarify definitions.
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A
acceleration: the time rate of change of velocity with respect to magnitude or direction;
the derivative of velocity with respect to time; unit of measurement is m/s2
activation energy: the minimum amount of energy required
to convert a normal stable molecule into a reactive molecule
atomic symbol: a notation using one to two letter to represent an element; the first letter
is always upper case and the second lower case
average: typical amount, rate, degree, etc.
B
balanced chemical equation: when there are an equal number of
atoms of each element on both sides of a chemical equation
billiard ball atomic model: the first model of an atom; developed in 1803 by (John) Dalton;
Dalton observed that the gases of air could be compressed only so far and concluded that air and all other matter is composed
of solid, indestructable particles (atoms) too tiny to see
binary compound: a compound composed of only two elements
blueberry muffin atomic model: also known as the "plum pudding" model; developed in
1897 by (Joseph John) Thompson as an improved model of the atom that included particles (electrons) scattered throughout
the solid mass of an atom; he had proven the existence of electrons as part of an atom through experiments
with the cathode ray tube
Bohr atomic model: developed by (Niels) Bohr in 1922; Bohr discovered fixed energy levels
for electrons and developed the model of the atom that shows electrons "orbiting" around the nucleus in fixed orbits (valence
shells), much like the layers of an onion
Boyles Law: the gas law that describes the relationship between pressure and volume;
for a fixed amount of gas at a constant temperature, pressure and volume are inversely proportional (For a more detailed explanation that might help clarify this law, click here.)
C
catalyze: to modify, especially to increase, the rate of a chemical
reaction
cellulose: a complex carbohydrate, (C6H10O5)n, that is composed of glucose units,
forms the main constituent of the cell wall in most plants; humans lack the ability to digest it
Charles Law: the gas law that describes the relationship between
volume and temperature; at constant pressure, volume and temperature are directly proportional (For practice using this law click here, but these problems are tough!)
chemical equation: a symbolic representation of a chemical reaction; reactants are on the
left side of the equation, and products are on the right
chemical reaction: the process by which one or more substances are
changed into others
coefficient: the large script number that precedes an element, compound,
or molecule that tells you the number of atoms of each element that follows it
compound: two or more atoms chemically combined
condensation: the process by which a gas becomes a liquid; energy is decreased enough so
that the attractive forces between molecules forces molecules into near proximity
D
dew point: the point of saturation
direct relationship: the relationship between two variables where both
variables change in the same direction to the same degree
E
electron cloud atomic model: a cloud-like model of the atom that describes
where an electron is likely to be found; (Erwin) Schrödinger took Bohr's model a little further by applying a probability
equation to the movements of electrons; it can not say with any certainty where
the electron actually is at any point in time, yet can describe where it ought to be; the probable locations of the electron
predicted by Schrödinger's equation happen to coincide with the locations specified in Bohr's model
element: substance that can not be broken down to a simpler substance by
ordinary chemical means
energy levels: the orbital paths an electron follows around the nucleus of an atom; the
first level can hold up to two electrons, while all other levels can hold up to eight electrons
evaporation: the process by which a liquid becomes a gas; enough energy is gained
so that molecules can escape the surface of the liquid
F
freezing: process by which a liquid becomes a solid; enough energy is removed so that the
attractive forces between molecules holds them in fixed positions
H
humus: the brown
or black organic substance in soil consisting of partially or wholly decayed vegetable or animal matter that provides nutrients
for plants and increases the ability of soil to retain water
I
ion: an electrically charged atom
ionic compound: a coumpound that is formed by ionic bonds
inference: a conclusion derived from observations and/or previous experience
inverse relationship: the relationship between two variables where one
variable changes in one direction and the other variable changes in the opposite direction to the same degree
instantaneous velocity: defined mathematically as the velocity at a given moment in time
K
kilometers: a unit of length in the metric system; the common measure of
distances equal to 1000 meters; equivalent to 3280.8 feet or 0.621 miles
M
molecule: a neutral group of atoms held together by covalent bonds
melting: process by which a solid becomes a gas; enough energy is gained to overcome
the attractive forces that hold molecules in fixed positions
meter: the fundamental (SI) unit of length in the metric system;
equivalent to 39.37 inches
N
neutron: an atomic particle having a neutral
charge
negative acceleration: when an object is slowing down the acceleration of the object is
in the opposite direction from the velocity
O
observation: facts about something gained through the use of the five senses
orbit: the path of a celestial body or an artificial satellite as it revolves around another
body
oxidation number: the apparent charge on an atom that indicates its charge after electrons
are gained or given up; written as a superscript (ex: Na3+)
P
point of saturation: the point at which the air can hold no more water; this is also known
as the dew point
polyatomic ion: a group of atoms covalently bonded but possessing an overall charge
polymer: a chemical compound or mixture of compounds formed by polymerization and consisting
essentially of repeating structural units
Q
qualitative: information about something using descriptive words (non-numerical)
quantitative: information about something that describes how much (numerical)
R
R group: the part of a protein that is the chemical variable where
different functional groups can be present; determines the different amino acids
S
speed: how fast something is moving; different from velocity because no direction is involved;
d/t; unit of measurement is m/s
subscript: the small number behind and below an element that
tells you the number of atoms of the preceding element only; in the case of a subscript behind parentheses, the subscript
applies to all elements within the parentheses
sublimation: the process by which a solid becomes a gas without ever becoming a liquid;
enough energy is gained so that molecules can escape the surface of the solid and go into the air
T
terminal velocity: the velocity at which a falling object moves through a medium
time: the system of sequential relationships
V
velocity: involves speed and direction; vf
–vi / t f
- t i; unit of measurement is m/s
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