Chemistry 105 Midterm 1

definite shape and volume

definite volume, indefinite shape

neither definite volume or shape, includes plasma

solid to gas

gas to solid

liquid to solid

solid to liquid

gas to liquid

liquid to gas

matter dependent property, independent of material quantity; i.e temperature, density

property independent of matter, dependent on quantity of substance; i.e mass, volume, length

observed/measured without changing a substance into another; easily reversible

observed only by reacting a substance to form another

process in which composition and structure change during a reaction

ability to do work

energy stored by position, internal stress, electrical charge, or other factors

energy of motion

matter is not created nor destroyed in any chemical or physical change

material that escapes when substance is burned

a chemical compound contains the same elements in exactly the same proportions by mass regardless of the size of the sample or source of the compound

elements can combine in different ratios to form different compounds

atoms are unchanged by a chemical reaction, elements are distinguished by the number of protons, can combine in different ways; small nucleus surrounded by electron cloud

shows the types and numbers of atoms combined in a single molecule of a molecular compound

indicates the kind, number, arrangement, and bonds but not the unshared pairs of the atoms in a molecule

shows patterns of arrangement, no structural elements

bonding arrangement showing spatial orientation and size comparison

overall shape, more accurate representation

closeness of measured value to true value

degree to which repeated measurements show the same result; express variance as a range

always significant

never significant

significant if decimal point is present

least number of decimal places

least number of sig figs

defined element; elements are not air, earth, water, fire; matter based on observation and demonstration

law of conservation of mass; accurate measurements, matter is neither created nor destroyed

law of definite proportions; pure substances consist of elements in definite/fixed proportions

law of multiple proportions; atomic theory; when mass of one element is fixed, masses of other element will be a ratio of whole numbers; elements composed of atoms

john dalton; indivisible hard spheres with hooks to form molecules

strength depends on magnitude of charge and distance between two charged particles

jj thomson; created stream of particles that can be deflected by magnet, proving negative particles existed. deflection by electric and magnetic field gave charge/mass ratio

1909, designed to measure electron charge. x-rays ionize air to transfer electrons onto droplets, magnetic field applied and charge measured based on the balance of gravity and charge

positively charged particles, studied uranium, explained that radioactivity is the spontaneous decomposition of atom

discovered x-rays in 1895

discovered radioactivity in 1896

positively charged particles with about four times the mass of a hydrogen atom; least penetrative

a negatively charged particle (a high speed electron) emitted from the nucleus of an atom during radioactive decay

the high-energy photon emitted by a nucleus during fission and radioactive decay; neutrally charged, highest penetrative ability

J.J Thomson; model of an atom where electrons were randomly distributed within a positively charged cloud; 1904

1909; solar system model of the atom, gold foil experiment; fired negative ions at thin sheet of gold foil, discovered the positively charged atomic nucleus and proposed a nuclear model of the atom in 1911

discovered the neutron in 1932

atoms of the same element that have different numbers of neutrons

russian chemist who developed a periodic table of the chemical elements and predicted the discovery of several new elements based on patterns in chemical properties (1834-1907)

groups or families that have similar properties, same number of valence electrons and similar charges

horizontal rows, have same number of electron shells

shiny solids (except mercury), high melting points, high densities, malleable, ductile (drawn into wires), good conductors of heat and electricity, form cations and basic oxides

dull, brittle, poor conductors of heat and electricity; form anions, ionic compounds, and acidic oxides

elements that have properties of both metals and nonmetals; antimony (Sb), germanium (Ge), silicon (Si), arsenic (As), tellurium (Te), polonium (Po), boron (B), and astatine (At)

group 1, always water soluble

group 2, sometimes water soluble, reactivity increases down group

group 17, diatomic, forms anions, reactivity increases up group, reacts with metals to form metal halides, disinfectants

group 18, unreactive, do not easily gain or lose electrons

the average mass of all the isotopes of an element

an instrument used to determine the relative masses of atoms by the deflection of their ions on a magnetic field; radius of curve depends on the mass and charge of particles

proposed in 1800s, described as moving wave of energy with two perpendicular oscillating fields

top of wave

bottom of wave

height of crest or depth of trough

distance between two corresponding parts of a wave

the number of complete wavelengths that pass a point in a given time

amount of energy per second carried through a unit area by a wave; amplitude squared

point of zero amplitude on a standing wave

gamma rays < x-rays < ultraviolet < visible < infra red < microwave < radio waves

violet > blue > green > yellow > orange > red

light defined by Maxwell's equations, motion defined by Newton's equations; most problems solved and understood

the electromagnetic radiation emitted from a heated solid

the emission of electrons from a metal when light shines on the metal

classic physics predicted spectrum of emitted blackbody radiation should extend without bound into the ultraviolet, resolved by Plank's hypothesis that the oscillating waves exchange energy in quanta

1900, light has particle like properties and wavelike characteristics; objects absorb/emit energy in small, specific quantities called quanta into the ultraviolet; related energy absorbed by matter to frequency of light emitted

no electrons emitted for low frequency light regardless of intensity; electrons emitted above specific threshold frequency; number of electrons emitted increases with intensity; velocity of ejected electrons increases as frequency increases beyond threshold

1905, concluded light itself is quantized in photons; classical views light as wave, einstein viewed light as particle; light is both

minimum amount of energy to remove one electron, any excess energy is converted to kinetic energy of ejected electron, cannot exceed energy of a single photon of wavelength λ

set of wavelengths

the emission of a continuous range of frequencies of electromagnetic radiation

1814, a set of dark lines in the otherwise continuous solar spectrum - sunlight is not continuous

1859, each element emits unique set of wavelengths

when an electron falls to a lower energy level, a photon is emitted, giving off colors

absorbed colors are subtracted from continuous spectrum in the appearance of black lines

a gas absorbs colors when cold that it emits when hot

a series of absorption or emission lines of hydrogen seen at visible wavelengths

1913, electrons can only occupy certain stable orbits, "allowed" orbits have quantized angular momentum and quantized energy; electrons can jump between orbits by absorbing or emitting light

principal quantum number, designates energy level and orbital size; 1, 2, 3, 4

ground state, lowest possible energy level

excited state

set of spectral lines that appear in the UV region when a hydrogen atom undergoes a transition from energy levels n>1 to n=1

set of spectral lines that appear in IR region when electron falls from n>3 down to n=3

approaches 0

limited to atom with single electron; doesn't explain WHY angular momentum and energy levels are quantized or why n=1 is lowest energy level

einstein says momentum=h/λ; shorter wavelength has higher momentum and light acts like a particle

moving objects have wave-like behavior; matter shows properties of both wave and particles