73 terms

Physics Ch. 2

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matter
anything that has mass and takes up space; anything having inertia
inertia
matter's unique property of resisting any change in its present state of motion
matter in motion will remain in motion
matter at rest will stay at rest
Newton's definition of inertia
mass
represents how much inertia an object has, or how much force is required to change the object's state of motion
weight
represents the amount of force the earth's gravity exerts on an object's mass
density
the ratio of an object's mass to its volume
ρ = m/v
equation for density
1 cm³
what 1 mL is equal to
specific gravity
the ratio of a given sample's density to a standard density
water
the standard for liquids and solids
hydrogen gas
the standard for gases
sp. gr. = ρ of sample/ρ of standard
equation for specific gravity
molecule
a chemical combination of two or more atoms
elemental molecule
if the elements are the same, the molecule is called __
compound
what a molecule is called if the atoms in a single molecule are different elements
pure substance
a substance containing only one kind of atom or molecule
mixtures
physical combinations of two or more elements or compounds
homogeneous
what a mixture is called if the particles of each substance are uniformly distributed throughout the mixture on a molecule-by-molecule basis
heterogenous
what a mixture is called if the mixture settles into layers of different particles or has large clumps of molecules
solid
type of matter that has a definite shape and volume
liquid
type of matter that has a definite volume and an indefinite shape
gas
type of matter that does not have a definite volume or shape
plasma
type of matter that is a highly ionized gas
atom
the basic building block of all matter
nucleus
a collection of particles fixed at the center of an atom
proton (p⁺)
a positively charged particle that gives the atom its identity as an element
atomic number
the number of protons in a given element; determines the atom's type
neutron (n⁰)
the largest atomic particle; has a neutral charge
mass number
states the sum of the number of protons and neutrons in the nucleus
isotopes
atoms with the same atomic number but differing mass numbers
atomic mass
the general mass of an element
atomic mass units
what atomic mass is measured in
electron (e⁻)
a negatively charged particle in the atom
ion
a charged particle that resulted from the loss or gain of electrons
anion
a negative ion
cation
a positive ion
element
any substance that cannot be broken down by chemical means into a simpler substance
periods
rows on the periodic table
groups
columns on the periodic table
valence electrons
electrons in the outermost electron layer
E = mc²
Einstein's equation relating mass and energy
photons
the tiny particles that make up light
1. mass gain
2. nuclear mass defect
the two implications of E = mc²
energy increases, mass increases
energy decreases, mass decreases
the relationship between mass and energy
subatomic particles
particles that are smaller than an atom
elementary particles
defined as having no components, no building blocks, and no smaller parts
electrons
of protons, neutrons, and electrons, the only one that is considered an elementary particle
quarks
smaller particles that make up protons and neutrons
hadron
any substance believed to contain quarks
mesons
hadrons containing two quarks
baryons
hadrons containing three quarks
gluon
believed to bind the quarks together
lepton
subatomic particles that do not contain any quarks
true
true or false: electrons do not contain quarks
neutrino
a particle that has a mass of virtually zero and travels virtually at the speed of light
positron
a positively charged electron
gamma radiation
an invisible, highly penetrating type of electromagnetic radiation that is extremely dangerous to humans
pair production
the process of gamma radiation passing through a heavy material, causing a photon to vanish and an electron and a positron to suddenly appear
electromagnetic radiation
any type of emitted energy
antiparticles
particles that have the exact same characteristics, but opposite charges
1. electron/positron
2. proton/antiproton
3. neutron/antineutron
the three main groups of antiparticles
false
true or false: antiparticles can exist in their opposite particles' presence
antimatter
what particles like the positron, the antiproton, and the antineutron are sometimes called
annihilation
occurs when a positron and electron collide and convert their combined masses into a form of energy; opposite of pair production
orbital
a region of high likelihood for finding an electron as it travels around the nucleus
electron capture
when a proton absorbs an electron as it is orbiting the nucleus; produces a radiated neutrino
heavy atoms
atoms with a neutron to proton ratio greater than 1:1
radioactive decay
the process that occurs when heavy atoms release energy to become more stable
alpha decay (α decay)
type of decay in which a nucleus emits a helium atom (two protons and two neutrons); perceived as a gentle warmth
two fewer
in alpha decay, the heavy element's identity is changed to an element with __ __ protons
beta decay (β decay)
type of decay in which a neutron is changed into a proton, emitting an electron
one greater
in beta decay, the heavy element's atomic number becomes __ proton __
half-life
defined as the time required for half a radioactive substance's mass to decay into something else