ACS Exam Flashcards
(156 cards)
1
Q
chemistry is a science based on…
A
modeling molecules with matter
2
Q
weight
A
force on an object due to gravity
3
Q
mass
A
quantity of matter
4
Q
hypothesis
A
statement made to try to explain an observable pattern in nature, often based on an unobservable causal entity
5
Q
relationship between volume and pressure
A
P∝F/A
6
Q
boyles law
A
V∝1/p
7
Q
atmospheric pressure
A
standard: 760 mm hg = 760 torr = 1 atm
8
Q
relationship between volume and temp of gas
A
ast temp increases, volume increases (however not directly proportional)
9
Q
absolute zero
A
lowest temp possible where molecular motion goes to a minimum (-273C) = 0K
10
Q
Volume is directly proportional to temp when…
A
temp is in K
11
Q
combined gas law
A
(P1V1 / T1 )= (P2V2 / T2)
Combination of charles law and boyles law
12
Q
charles law
A
V/T=K (for temp in K)
13
Q
precision
A
reproducibility of results
14
Q
accuracy
A
closeness to correct value
15
Q
density
A
density= mass/volume
16
Q
algorithm
A
a step by step procedure that can be applied to solve a problem
17
Q
true problem
A
a problem for which no algorithm can be applied
18
Q
matter
A
something that has mass and occupies space
19
Q
liquid
A
indefinite shape, definite volume
20
Q
solid
A
definite shape, definite volume
21
Q
gas
A
variable shape and volume
22
Q
pure substance
A
one kind of matter, distinct physical and chemical properties
23
Q
compound
A
a pure substance that can be broken down into 2 or more pure substances
24
Q
element
A
a pure substance that cannot be decomposed into other pure substances by ordinary chemical means
25
physical change
new form of same substance
26
physical properties
measurable and detectable by the senses
27
mixture
sample of matter composed of 2 or more chemicals
28
homogeneous/solution
uniform appearance and composition throughout
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heterogenous
visibly different phases and/or different composition in a sample of matter
30
chemical change
old substance destroyed, new substance formed
31
distillation
the process of separating the components of a mixture by heating the liquid and collecting the gaseous components that separate.
32
conservation of mass
total mass of the substances that undergo a chemical transformation is equal to the total mass of the products that change (lavoisiers fruit experiment)
33
law of definite proportions
any individual compound is made of the same invariable ratio of more elementary substances by mass
34
law of multiple proportions
when 2 substances react to form more than one product, the amounts of one that completely reacts with a fixed amount of the other are in a reaction of small whole numbers
35
law of combining volumes
the volume ratio in which gases react are always ratios of small whole numbers
36
avagadros hypothesis explains the law of combing volumes by proposing..
equal volumes of gases contain equal numbers of molecules
37
atomic mass unit (u)
one atom of carbon12 has exactly 12u, 6.02E-23=1g
38
atomic number
number of protons
39
every atom of a particular element has the ______ number of protons
same
40
mass varies among atoms of the same element because of
varying number of neutrons
41
isotopes
atoms of the same element that have different masses, different # of neutrons
42
mass number
the total number of protons and neutrons in the nucleus
43
atomic mass of an element
average mass of all atoms of an element as they occur in nature.
44
periods of periodic table
horizontal rows
45
groups of periodic table (chemical families)
vertical columns consisting of elements with similar properties
46
diatomic molecules
each molecule has 2 atoms (superheros night out, fire can burn ice)
47
polyatomic molecules
each molecule has many atoms
48
two polyatomic molecules to remember
sulfur-sexy 8s, phosphorous- foxy 4s
49
state symbol
follows element symbol and represents state at 25C and 1 bar
50
2 elements that are liquid under ordinary conditions
Hg(mercury) Br(bromine)
51
binary molecular compounds
compounds formed by 2 nonmetals or a metalloid and a nonmetal
52
amonia
NH3
53
cations
positively charged ion
54
anion
negatively charged ion
55
ion
atom that gained or lost an electron
56
ionic compound
metal ion- non metal ion compound
57
acids
a molecular compound that reacts with water to yield a hydrogen ion and an anion
58
oxoacid
an acid that contains hydrogen, a nonmetal, and oxygen
59
mole
one mole is that amount of any substance that contains the same number of units as the number of atoms in exactly 12 grams of carbon12 (6.02E23)
60
empirical formula
shows the simplest ratio of atoms of the elements in a compound
61
what occurs during a chemical change
of atoms stay the same but # and type of molecules changes
62
signs of chemical change
color change, formation of gas/solid, heat, light
63
aqueous solution
dissolves in h20
64
base
substance that contains hydroxide ions
65
neutralization reaction
acid+base➞water+salt
66
ideal yield
calculated, amount of product formed from complete conversion of given amount of reactant to product
67
actual yield
amount determined by experiment
68
percent yield
actual/ideal x 100
69
daltons law of partial pressures
the total pressure exerted by a mixture of gases is the sum of the partial pressures of the gases in the mixture.
70
Ideal gas law
PV=nRT
71
volume of gas at standard temp and pressure
22.7 L/mol
72
law of conservation of energy
in a non-nuclear change, energy is conserved, neither created nor destroyed.
73
energy definition
the ability to do work or transfer heat
74
work equation
W=FxD
75
one joule
force of one newton exerted over one meter
76
heat definition
form in which energy is transferred between substances of different temperatures.
77
temperature
the measure of the average energy of particles in a substance
78
exothermic reaction
chemical change that releases energy to tis surroundings
79
endothermic reaction
chemical change that absorbs energy from its surroundings
80
calorie
the amount of energy required to raise temperature of 1g of water 1C
81
thermodynamic system vs surroundings
the portion of the universe under consideration vs everything outside the system
82
state function
a property whose value is determined only by the state of a system at a given moment
83
internal energy
energy of a system that results from sources other than the influence of external force
84
1st law of thermodynamics in words
the internal energy of a system changes by an amount equal to the sum of the heat that flows into or out of the system and the work done by the system.
85
1st law of thermodynamics in math
△E=q+w
86
enthalpy definition
the heat content of a system
87
enthalpy of reaction definition
heat given off or absorbed in a chemical reaction
88
specific heat
the heat flow required to change the temp of 1 gram of a substance by 1C
89
calorimeter
isolated segment of the universe, a system that cant transfer heat to or from its surroundings
90
hess's law
if a reaction is carried out in a series of steps, the △H for the total reaction is equal to the sum of the △H for the steps
91
speed of light (c)
3.00E8 m/sec
92
wavelength (ƕ)
distance between identical parts of a wave
93
frequency (v)
of complete waves passing a point in a given period of time
94
white light produces a ______ spectrum
continuous
95
elements produce a _____ spectrum
line
96
photon
energy is released by electrons in the form of a massless pocket of electromagnetic radiation (photon)
97
wave particle duality
light acts as a wave and a particle
98
hertz
one inverse second
99
velocity
c = ƕv
100
plancks constant
relates energy of a photon to its frequency
| h = 6.02E-34 JxS
101
energy frequency proportionality
E = hv
102
photoelectric effect
light can cause the ejection of electrons from some metal surfaces
103
Bohr model
- energy possessed by electron and radius of its orbit is quantized
- quantized energy levels, at any instant the electron may have one of several energy levels but can never be in between
104
quantum leap
process by which electrons move between orbits, disappear from one orbit and reappear in another
105
ground state
condition in which all electrons in an atom occupy the lowest possible energy levels
106
excited state
condition at which one or more electrons in an atom has an energy level above ground state
107
equation for wavelength of a moving particle
ƕ = h/mv
108
probability density
the probability that a particle is found in a specified 3-d region in space
109
pauli exclusion principle
at any instant, an orbital may be
1. unoccupied
2. occupied by one electron
3. occupied by 2 electrons
110
hunds rule
the most stable arrangement of electrons in a sublevel is the one that has the max # of unpaired electrons
111
valence electrons
total # of s and p electrons in the highest occupied energy level
112
effective nuclear charge
the charge experienced by an electron in a many-electron atom (actual charge-shielding constant)
113
atomic radius
average distance b/w the nucleus of an atom of the element and the outer limit of its electron cloud
114
ionization energy
the energy required to remove one electron from a neutral gaseous atom of an element
115
electron affinity
the change in energy that occurs when an electron is added to a gaseous atom or ion (generally increases from left to right)
116
an element is a metal if...
it can lose one or more electrons and become a positively charged ion, if not is a nonmetal
117
crystal
definite geometric structure of a solid
118
ionic bonds
strong electrostatic forces that hold the ions of a crystal in a fixed position
119
ionic compound
compounds made up of ions
120
molecular compounds
ultimate structural unit is an individual particle known as a molecule
121
covalent bonds
atoms in a molecule share electrons
122
what causes the octet rule
tendency towards a complete octet of electrons in a bonded atom is due to a systems tendency to move to lowest energy state possible
123
nonpolar bonds
a bond in which bonding electrons are shared equally
124
polar bond
electrons are shared unequally
125
electronegativity
ability of an atom to attract bonding electrons to itself (increases left to right, bottom to top)
126
constitutional isomer
made of the same atoms but connected differently
127
resonance structures
series of lewis diagrams that show the different possible distributions of valence electrons
128
resonance hybrid
single unchanging average, represents actual molecule state
129
Free radicals
species with an odd # of electrons
130
bond order
(# of shared electron pairs)/(# of links)
131
bond length
average distance between the nuclei of 2 atoms in a molecule
132
calculating △H using bonds
△H= E of bonds broken- E bonds formed
133
electrolysis
movement of ions that make up an electron current in a solution
134
molecular compounds do/dont conduct electricity
dont (no ions)
135
strong electrolyte
substance whose solution is a strong conductor
136
non-electrolyte
substance that does not conduct electricity
137
strong acid
almost all the molecules of the original compound are converted to ions (major species are ions, minor species are un-ionized molecules)
138
weak acid
only slightly ionized in solution
139
seven common strong acids
HNO3, H2SO4, HCl, HClO3, HClO4, HI, HBr
140
Ions are the major species in two types of solutions
1. ionic compounds
| 2. 7 strong acids
141
allotrope
different physical forms in which an element can exist
142
alpha particle
produced during alpha decay, fast moving helium nucleus
143
Periodic table groups
Alkali Earl Takes Happy Naps
144
Titration
careful addition of one solution to another by means of a device that can measure volume accurately
145
liquid properties vs gas properties
1. gases can be compressed, liquids cannot
2. gases expand to fill their container, liquids do not
3. gases have low densities, liquids do not
4. gases can be mixed in a fixed volume, liquids cannot
146
vapor pressure
partial pressure exerted by evaporated gaseous particles
147
molar heat of vaporization
energy required to change one mole of a liquid to a gas at standard temp and pressure
148
viscosity
internal resistance of a liquid to flow
149
surface tension
tendency of a liquid to arrange for minimum surface tension
150
dipole forces
attraction b/w the positive pole of one molecule and the negative pole of another molecule (requires polar molecules)
151
induced dipole forces
attractions b/w substances w/ non polar molecules resulting from shifting electron clouds
152
hydrogen bonds
hydrogen bonded to an atom that is small and highly electronegative (nitrogen, oxygen, fluorine)
153
covalent bond
bond in which atoms share electrons to form octet, (occurs between a nonmetal and a nonmetal, or a nonmetal and a metalloid)
154
ionic bond
bond in which one atom loses an electron and another atom gains it to form an octet (occurs between nonmetal and metal)
155
an ionic bond is _____ than a covalent bond
stronger
156
sigma bond
type of covalent bond where orbitals overlap end to end
