Chemistry Midterm Review

Mass
Quantity of matter in an object
SI base unit: kg
volume
space that an object occupies
SI base unit: mL cm3
solid
fixed volume and shape; particles vibrate
liquid
fixed volume but not shape; particles slip past each other.
gas
no fixed volume or shape. fastest moving particles
1 cm3 =
1 mL
1 dm3 =
1,000 mL or 1 L
allotrope
one of a number of different molecular forms of an element. such as; O2-oxygen and O3-ozone
formula for density
d=m/v
2 groups that make up pure substances
elements and compounds
law of conservation of energy
Mass of product equals the mass of the reactants
Law of Conservation of Energy
The total quantity of energy remains constant. It cannot be created or destroyed.
Kelvin to Celcius
-273
Celcius to Kelvin
+273
scientific method
Specific procedures for conducting research -make/test hypothesis
-observe
-draw conclusions
-publish results
-construct theory
theory
a well-tested explanation of observations. Can be disproved but not fully proven
hypothesis
a reasonable and testable explanation for observations
confined zeros
significant
leading zeros
not significant
trailing zeros following a decimal point
significant
qualitative
describing something with properties such as texture and color used to describe quality
quanttative
describing something with numbers
chemical change
identity changes. new substance forms
-evolution of gas
-precipitate forms
-release(exothermic) or absorption(endothermic) of energy
-color change
physical change
identity does not change. can change state/mix but remain the original substance
law of definite proportions
two samples of a given compound are made of the same elements in the proportions by mass regardless of the sizes of sources of the samples
law of multiple proportions
if two or more different compounds are composed of the same elements, the ratio of mass in the second one is always a ratio of small whole numbers
Daltons theory
1(revised)
all matter is composed of extrememly small particles called atoms that cannot be subdivided or destroyed
Daltons theory
2 (revised)
Atoms of a given element are identical in their physical and chemical properties
Daltons theory
3
Atoms of different elements differ in their physical and chemical properties
Daltons theory
4
Atoms of different elements combine in simple, whole-number ratios to form compounds
Daltons theory
5
In chemical reactions, atoms are combined, rearranged, or separated but NEVER created or destroyed.
which subatomic particles reside in the nucleus?
protons-positive
neutrons- no charge
subatomic particle outside the nucleus
electrons- negative
isotope
Atoms of the same element with a different number of NEUTRONS
ion
an atom, radical or molecule that has gained or lost one or more electrons and now has a neg or pos charge
what happens when an electron gains energy
it moves into an excited state
returning from an excited to ground
it releases a specific quantity of energy and quickly falls back to its ground state
Principal quantum number (n)
indicates main level energy occupied by the electron ~1,2,3,4
Angular quantum number (l)
indicates the shape or type of orbital that corresponds to a particular sublevel
=0(s);
=1(p);
=2(d);
=3(f)
Magnetic Quantum Number (m)
is a subset of the L quantum number. indicates the number/orientations around the nucleus
1-s orbital
3-p orbitals
5-d orbitals
7-f orbitals
orbitals/electrons in s
1 orbital; 2 e-
orbitals/electrons in p
3 orbitals; 6 electrons
orbitals/electrons in d
5 orbitals; 10 e-
orbitals/electrons in f
7 orbitals; 14 e-
aufbau
“building up”
e- fill orbitals with lower energy first
s>p>d>f
Hund’s
orbitals of the same n and L quantum numbers are each occupied by one before paring occurs
Pauli
two particles of a certain class cannot be in the exact same energy state ^^ or vv
Periodic Law
The physical or chemical properties tend to repeat systematically with increasing atomic number
4f
lanthanide
5f
actinide
4f or 5f radioactive?
5f- actinides
malleable
can be hammered into a sheet and remain conductive
ductie
can be stretched into thin wire and remain conductive
electron sheilding
outer, valence e- held less tightly to nucleus
down a group, e- shielding
atomic radius increases down a group
as the nuclear charge increases across a period
the effective nuclear charge also increases
ionization energy
the amount of energy needed to remove an electron from an atom
ionization energy
-decreases
-increases
ionization energy
-down a group
-across a period
electronegativity
a measure of the ability of an atom in a chemical COMPOUND to attract electron
electronegativity
-decreases
-increases
electronegativity
-down a group
-across a period
electron affinity
the change in energy when a neutral atom gains an electron
electron affinity
-decreases
-increases
electron affinity
-down a group
-across a period
ionic radii
-increases
-decreases
ionic radii
-down a group
-across a period
atomic radii
-increases
-decreases
atomic radii
-down a group
-across a period
group 1
1+
group 2
2+
group 15
3-
group 16
2-
anion
ion with a negative charge
cation
an ion with a positive charge
common between an ion and its parent atom
proton count
lattice energy
the amount of energy released when an ionic bond is formed
bond energy
energy required to break the bond of 1 mole of a chemical compound
properties of ionic compounds
-hard and brittle
-good conductors
-strong
-high boiling and melting points
-solid at room temp
for an ionic compound to conduct
-substance must contain charged particles
-must be free to move
strongest attractive forces
ionic
why are ionic compounds considered brittle?
when you apply a strong force, fracture occur, not dents
CH3COO(1-)
acetate
S2O3(2-)
thiosulfate
NO2(1-)
nitrite
NO3(1-)
nitrate
PO4(3-)
phosphate
CO3(2-)
Carbonate
CN(1-)
cyanide
CrO4(2-)
Chromate
SO4(2-)
Sulfate
SO3(2-)
Sulfite
OH(1-)
Hydroxide
MnO4(1-)
Permaganate
Cr2O7(2-)
Dichromate
NH4(2-)
Ammonium
Covalent Bond stronger/weaker than ionic
weaker than ionic
weakest type of covalent bond
nonpolar covalent
tetrahedral
atoms:
bonds:
tetrahedral
5
4
0-0.5
nonpolar
.6-2.0
polar covalent
2.1-4
ionic compound
avogrados number
6.022×10^23
molar mass
an average of the abundances of each weight of the element
mass>particle
mass given| 1 mol | avogrados#
……….|molar mass|1mol
particle>mass
Part. given| 1 mol | molar mass
………|avorgado#| 1 mol
1A
alkali
2A
alkaline earth
17A
halogens
18
noble gases
3-12
transition metals (d block)
which in d block break Aufbau to become more stable?
Cromium and Copper
x

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