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Flashcards in midterm Deck (172):
1

chemistry

study of composition, structure, and properties of matter and the changes it undergoes

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chemical

any substance that has a specific composition

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organic chemistry

study of substances containing carbon

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inorganic chemistry

study of substances that do not contain carbon

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physical chemistry

study of interrelationships between energy and matter

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analytical chemistry

identification of substances and determination of the composition

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biochemistry

study of processes that occur in living things

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theoretical chemistry

uses math and computers to explain and make predictions

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basic research

increasing knowledge, googling something, asking how? and why?

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applied research

solve a problem

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technological development

production and use of products that make something to improve our quality of life

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atom

smallest unit of an element that maintains the properties of that element

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element

a pure substance made up of only one kind of atom. building blocks of matter. organized on the periodic table

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weight

measure of the Earth’s gravitational pull for matter; use a scale, measurement is pounds

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mass

measure of the amount of matter in a substance; use a balance, unit is grams

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matter

anything that has mass that takes up space

ex. water
not ex. light, energy

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inertia

resistance to change in motion

ex. space, fidget spinner

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law of conservation of mass

matter cannot he created or destroyed in ordinary chemical reactions

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extensive property

depends on the amount of matter

ex. volume, mass, shape

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intensive property

does not depend on amount of matter

ex. density, melting point, boiling point

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physical property

can be observed or measured without altering identity of substance

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physical change

any change that does not change identity of substance

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chemical property

ability of a substance to undergo a change that alters its identity

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chemical change

a change in which new, different substances are formed (a change to its identity)

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solid

definite volume, definite shape, closely packed, rotational motion of particles

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liquid

definite volume, indefinite shape, not as closely packed particles, rotational and vibrational motion

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gas

indefinite volume, indefinite shape, widely spaced particles, rotational, vibrational, and translational motion

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plasma

high temperature state in which atoms lose electrons

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reactant

substances that overgo a change

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product

substances that are formed

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evidence of a chemical change

test products, gives off heat or light, production of gas/bubbles, formation of a precipitate

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chemiluminescence

gives off light

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exothermic

gives off heat

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endothermic

takes in heat

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precipitate

a solid that separates from a solution

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energy

ability to cause change or ability to do work

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kinetic energy

energy of motion

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potential energy

stored energy

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law of conservation of energy

energy can be converted from one form to another, cannot be created or destroyed

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law of conservation of mass and energy

matter and energy cannot be created or destroyed

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mixture

blend of 2 or more kinds of matter, each keeps its own properties, can be separated physically

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heterogeneous mixture

one that is not uniform throughout

ex. salt and pepper, pizza, granite

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homogeneous mixture

one that is uniform in composition, solution

ex. salt water

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pure substance

same composition; cannot be separated by physical means (you lose all original properties when separating)

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element (pure substance)

cannot be decomposed by any ordinary change (physical or chemical)

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compound (pure substance)

can be decomposed into 2 or more simpler substances chemically

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law of definite composition

a chemical compound contains the same elements in exactly the same proportion by mass regardless of size

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laboratory chemicals and purity

it is important that chemicals in the lab remain pure - avoid contamination

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groups

vertical columns, elements very similar to each other in a family

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periods

horizontal rows

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metals

left side of the PT, good conducted of heat and electricity, luster, ductile, malleable

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nonmetals

right side of the PT, poor conductors

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metalloids

along step ladder, semiconductors

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system

specific portion of matter that has been selected for study

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scientific method

logical appeal to solve a problem

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steps of the scientific method

1) observing and collecting data
2) generalization
3) theorizing
4) testing

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quantitative data

numerical

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qualitative data

descriptive

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hypothesis

testable statement

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law

statement that describes facts

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unit of measurement

a physical quantity of a defined size

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SI

International System of Units, metric system, adopted in france

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SI base units

standard of measure, have a defined size

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examples of SI base units
length
mass
time
temperature

meter (m)
kilogram (kg)
seconds (s)
Kelvin (K)

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derived unit

obtained from combining base units

ex. area= meters squared
volume= meters cubed
speed= m/s
density= kg/meters cubed, g/mL, or g/ centimeters cubed

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factor label method

problem solving method using algebra

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accuracy

closeness of a measurement to the true or accepted value (how close values are to each other) (arrows all close to the center)

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precision

agreement among the values (arrows close to each other, doesn’t matter placement)

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percent error

(experimental value - accepted value)
——————————————————
accepted value

x100%

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sig figs

gives the amount of detail in a measurement, all non-zero numbers and sandwiched zeros are significant. leading zeros are not. tail zeros are if a decimal point is written

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scientific notation

used to represent very big or very small numbers

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temperature

measure of the average kinetic energy of the particles in a sample

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heat

sum total of the kinetic energy of the particles in a sample (more particles=more heat)

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thermometer

device used to measure temperature

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if liquid is warmer than the thermometer...

heat enters the thermometer, particles of the thermometer liquid move faster, liquid in the thermometer expands, liquid moves up the tube until temperatures are equal

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Kelvin conversion to Celsius, boiling point and freezing point

K=C + 273.15
fp= 273.15K
bp= 373.15K

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variable

quantity that can change

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directly proportional

one goes up, other goes up, y=kx

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inversely proportional

one goes up, other goes down, y=k/x

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dalton’s atomic theory

1) all matter is composed of extremely small particles called atoms
2) atoms in a given element are identical in size, mass, and other properties
3) atoms can be divided, created, or destroyed
4) atoms of different elements can combine in simple while number ratios to form compounds
5) in chemical reactions, atoms are combined, separated, or rearranged

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modern atomic theory

atoms can differ from each other (isotopes)
an atom is made of smaller parts
law of conservation of matter = in ordinary reactions

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chemical reaction

transformation of substances into one or more new substances

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definite proportions/definite composition

a chemical compound contains the same elements in exactly the same proportions by mass

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law of multiple proportions

if 2 or more compounds are composed of the same 2 elements, the proportions of those elements will be different

ex carbon dioxide (CO2) vs. carbon monoxide (CO)

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nucleus

center of an atom, protons and neutrons

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electron “cloud”

area surrounding nucleus containing electrons

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cathode ray tubes

have a + and - charge, used to form images in the form of light, proved electrons were real

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JJ Thompson

discovered the electron. did experiments with CRT and found that the charge to mass ratio was always the same

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Ernest Rutherford

discovered the nucleus and concluded atoms are mostly empty space using the gold foil experiment

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nuclear forces

forces that hold nuclear particles together and binds protons and neutrons into the atomic nucleus

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atomic number

number of protons in nucleus, determines the identity of the element

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isotope

atoms of the same element with varying number of neutrons (affects the mass)

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nuclide

general term for an isotope of any element (synonym)

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mass number

total number of protons and neutrons. each atom has a unique mass number. varies in isotopes

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isotopes of hydrogen

protium, deuterium, and tritium

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protium

one proton, one electron

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deuterium

one proton, one neutron, one electron

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tritium

one proton, two neutrons, one electron, radioactive

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average atomic mass

weighted average of the atomic masses for all known isotopes. calculates based on how much of each and how heavy each is

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calculating average atomic mass

mass of individual isotope x abundance (% of sample it is) = #

repeat until last one

add together

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mole

SI unit for amount of substance, counting unit

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molar mass

mass of 1mol of substance - on PT

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a dual nature

electrons have both wave-like and particle-like properties

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electromagnetic radiation

form of energy that exhibits wave-like behavior as it travels through space

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wavelength

distance between 2 corresponding points on adjacent waves

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frequency

number of waves that pass a given point in a specified time

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quantum

minimum quantity of energy that can be lost or gained by an atom

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photon

individual quantum of light

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bohr model

describes electrons as particles, single electrons orbit around the nucleus and each orbit has a specific energy but this only worried with hydrogen

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orbits

the circular paths electrons followed in the bohr model of the atom

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Heisenberg uncertainty principle

it is impossible to determine simultaneously the position and velocity of an electron

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electron configuration

arrangements of electrons in atoms

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aufbau principle

an electron occupies the lowest energy first

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hund’s rule

place one electron in each equal energy orbital before pairing

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valence electrons

electrons in the outermost shell, have the highest principle quantum number and determine many properties of the atom

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stanislao cannizzaro

found a method to determine atomic mass

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dimitri mendeleev

“father of the periodic table” made the first periodic table and noticed trends and left empty spaces for missing elements

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henry moseley

found a method to determine atomic number

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periodic law

properties of elements are based on atomic number and valence electrons

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group 1

alkali metals, soft, extremely reactive

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group 2

alkaline earth metals, less reactive than group 1

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group 17

halogens, very reactive

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group 18

noble gases, very unreactive, stable and full octet

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transition metals

luster, conductive, malleable, ductile

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strength of the nucleus

across=stronger
down=weaker

126

atomic radius

across=smaller
down=bigger

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ionization energy

energy to remove an electron
across=increases
down=decreases

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electron affinity

energy change when an electron is added
across=easier (exothermic)
down=harder (endothermic)

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electronegativity

ability to attract electrons
across=increase
down=decrease

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cation

ion with a positive charge, lost electrons

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anion

ion with a negative charge, gained ions

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chemical bond

a link between atoms

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ionic bond

a chemical bond between a cation and an anion caused by a transfer of electrons

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metals

left side of PT, losers, weak

135

nonmetal

right side of PT, grabbers, strong

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covalent bond

a bond caused by a sharing of electrons between a nonmetal and a nonmetal

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nonpolar covalent

equal sharing of the electrons

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polar covalent

unequal sharing of the electrons

139

metallic bond

metals only, electrons free to move about

140

molecule

a group of atoms held by covalent bonds

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diatomic molecule

molecule with only 2 atoms

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single bond

one pair of electrons shared between two atoms

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double bond

two pairs of electrons shared between two atoms

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triple bond

three pairs of electrons shared between two atoms

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molecular compounds

covalent bonds, individual molecules, strong bonds, low mp/bp, connect the dots drawing

146

ionic compounds

ionic bonds, crystal lattice, very strong bonds, high mp/bp, drawing = arrows with charges

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metallic bonding

metals lose electrons to the electron sea where they are free to move about and are shared by all atoms

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VSEPR

Valence Shell Electron Pair Repulsion Theory, valence electrons move as far away from each other as possible

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dipole

molecule with overall charge

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nonpolar with polar sites

molecules with an area of charge which cancel out

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nonpolar

molecule with no areas of charge

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how can you tell if a molecule is a dipole, NPWPS, or nonpolar?

is there a charge?
no=nonpolar
yes= can it be sliced?
no=NOWPS
yes=dipole

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intermolecular forces

the attraction between molecules

154

dipole-dipole interactions

occur due to attraction between partial charges with two dipoles. strongest external bond

155

hydrogen bond

external bond that involves a hydrogen atom

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london forces

occurs between nonpolars or NPWPSs. very weak connection

157

cobalt

2,3

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copper

1,2

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chromium

2,3,6

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iron

2,3

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silver

+1

162

platinum

2,4

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mercury

Hg2+2, Hg+2

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zinc

+2

165

cadmium

+2

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manganese

2,4

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nickel

2,3

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gold

+3

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molar mass

sum of average atomic masses for all elements in a compound

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percent composition

percent by mass of an element in a compound

171

empirical formula

the simplest (most reduced) formula

172

molecular formula

non-reduced formula