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Flashcards in Chemistry Deck (33)
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1
Q
matter
A
has mass and takes up space
2
Q
ground state
A
most stable state. state in which all electrons are at their lowest possible energy level
3
Q
controlled variable
A
experimental conditions that remain constant
4
Q
density
A
mass divided by volume
5
Q
endothermic
A
energy is added to change state
(boil, evaporation, melting, sublimation)
6
Q
exothermic
A
energy loss to change state
(condense, solidify, freeze, deposition
7
Q
BIN MIX
A
breaking is endothermic-energy in
making is exothermic - energy out
8
Q
atom
A
smallest unit of a substance that behaves like a substance, mostly empty space
9
Q
energy
A
the ability to change or to move matter
10
Q
sublimation
A
change of a substance from a solid directly to a gas
11
Q
electrons
A
located on the outermost part of the neutron around the nucleus, have a negative charge, experiments with cathode rays let to the discovery of them.
12
Q
atomic number
A
number of protons in that atom. all atoms of the same element have this.
13
Q
neutron
A
neutral charge, found in the nucleus
14
Q
proton
A
positive charge, found in the nucleus of an atom
15
Q
mass number
A
number of protons plus neutrons
16
Q
Dalton's atomic theory
A
atoms of each element are identical in size, mass, and other properties, his theory has been expanded and modified.such as "atoms cannot be divided"
says: in chemical reactions, atoms are combined, separated, or rearranged; all matter is composed of extremely small particles called atoms, and atoms cannot be divided, created or destroyed.
dalton thought that atoms cannot be broken down further . Not apart of his theory: an atom consists of a nucleus and a cloud of electrons. df
17
Q
atomic theory
A
atoms of the same element may have different masses
18
Q
law of definite proportions
A
states: any two samples of KC1 have the same ratio of elements, agrees with Dalton's atomic theory. the fact that every sample of a [articular chemical compound contains the same elements in exactly the same proportions by mass.
if two or more compounds are composed of the same two elements, then the ratio of the masses of the second element that is combined with a certain mass of the first element is always a ratio of small whole numbers.
19
Q
Rutherford
A
in his experiment, most of the particles passes through the foil. which led him to conclude that atoms contain massive central regions that have a positive charge. Rutherford concluded that atoms were mostly empty space. identified the nucleus of the atom
20
Q
dependent variable
A
variable that reacts to the independent date
21
Q
constant
A
factor held constant, kept the same
22
Q
independent variable
A
variable that is changed
23
Q
physical property
A
observed with the senses and can be determined without destroying the object
24
Q
chemical property
A
indicates how a substance reacts with something else. The original substance is fundamentally changed in observing this.
25
Q
solidify
A
change from a liquid to gas
26
Q
condense
A
the change from a gas to a liquid
27
Q
sublimation
A
the change from solid directly to gas
28
Q
deposition
A
the change from gas directly go solid
29
Q
significant figures
A
all non 0 numbers are significant, any 0 sandwiched btwn numbers are sig, trailing zeros (on right side) without decimal point are not sig, with decimal point the tailing 0s are sig. lead 0 are not sig.
30
Q
multple proportions
A
Law which states that when elements combine, they do so in the ratio of small whole numbers (assuming they have the same type of chemical bonds).
31
Q
KHDBDCM
A
kili, hecto, deka, base unit, deci, centi, milli v
32
Q
definite proportions
A
states that a chemical compound always contains exactly the same proportion of elements by mass.
33
Q
The theory of Democritus
A
held that everything is composed of "atoms", which are physically, but not geometrically, indivisible; that between atoms, there lies empty space; that atoms are indestructible; have always been, and always will be, in motion;