97 terms

Chemistry Semester 2 Review


Terms in this set (...)

homogenous mixture of 2+ substances universally dispersed thoughout a single phase
capable of dissolving in a particular solvent
mixture in which particles of a material are more or less evenly dispersed throughout a liquid/gas
a mixture consisting of tiny particles that are intermediate in size between those in solutions and those in suspensions and that are suspended in a liquid solid or gas
tyndall effect
when light is scattered by colloidal particles in a transparent medium
a substance that dissolves in water to give a solution that conducts an electric current
factors affecting rate of dissolution
increasing surface area of solute speeds up dissolution.
agitating (stirring, shaking, etc) the solution speeds up the dispersion of particles, and therefore dissolution.
heating the solvent increases rate of dissolution.
the ability of one substance to dissolve in a another at a given temperature and pressure; expressed in terms of the amount of solute that will dissolve in a a given amount of solvent to produce a saturate solution
solvent vs. solute
solute is dissolved by the solvent
polar vs. nonpolar
polar: bent/asymmetrical, partial charges, stronger bonds
nonpolar: symmetrical in all directions, no charge, weaker bonds
concentration of molecules in a substance (moles/Liter)
the process of lowering the concentration of H or Oh ions in a substance (adding H2O)
collision theory
The number of new compounds formed in a chemical reaction is equal to the number of molecules that collide x a factor that corrects for low energy collisions
activation energy
Energy required to start a reaction
activated complex
molecule in an unstable state intermediate to the chemicals and products in the chemical reaction
A substance that changes the rate of a chemical reaction without being changed or consumed significantly
exo vs endo diagram
Exo- releases and becomes hot; endo absorbs and becomes cold
percent yield
what you get/ accepted x 100
limiting vs excess reactant
Balance equations, and use the amount of each substance given to determine how many moles are needed. Then compare the values to the BEMR and see which one limits the other
properties of gases
tiny particles that are far apart, elastic collision= no net loss of kinetic energy, continuous, rapid motion, no forces of attraction, temperature depends on average kinetic energy
diffusion vs effusion
diffusion-spontaneous mixing of the particles of two substances caused by their random motion
effusion- process by which gas particles pass through a tin opening
real vs ideal gas
ideal gas- hypothetical gas that perfectly fits all the assumptions of the kinetic molecular theory
real gas- gas that does not behave completely according to the assumptions of the kinetic molecular theory
properties of liquids
definite volume and takes shape of container, particles in constant motion, greater attractive forces, particles not fixed-fluid, relatively high density, relative incompressibility, ability to diffuse
surface tension
a force that tends to pull adjacent parts of a liquid's surface together, thereby decreasing surface area to the smallest possible size
process by which a liquid or solid changes to a gas
process by which particles escape from the surface area of a non boiling liquid and enter the gas state.
equilibrium vapor pressure
properties of solids
closely packed, strong attractive forces, only vibrational movement, ordered particles, definite shape and volume, definite melting point, high density and incompressibility, low rate of diffusion
melting, melting point
melting- physical change of a solid to a liquid by the addition of energy as heat
melting point-the temperature at which a solid becomes a liquid
ionic crystals
positive and negative ions arranged in a particular pattern. Group 1/2 Metals combine w/ Group 16/17 nonmetals
crystal lattice
an array of 'small boxes' infinitely repeating in all three spatial directions.
the energy absorbes/released as heat in a chemical or physical change is measured on a calorimeter
measure of the average kinetic energy of the particles in a sample of matter
energy transferred between samples of matter bc of a difference in their temperatures
specific heat capacity
amount of energy required to raise the temp of 1 gram of a substance by 1 degree celsius
enthalpy of reaction
the quantity of energy transferred as heat during a chem rxn
solid to liquid state- no temp change
solid--->gas without a phase change through liquid
phase change diagram- triple point
triple point- all three phases observable
physical properties of water
melting/ freezing point- 0 degrees celsius
boiling/condensing point- 100 degrees celsius
Hess's Law
the overall enthalpy change in a reaction is equal to the sum of enthalpy changes for the individual steps in the process.
the force per unit area on a surface; pressure = force/area
Standard Temperature and Pressure- 273 degrees Kelvin/0 degrees celsius and 1 atm
Dalton's Law
Law of partial pressures
Properties of Acids
1. aqueous solutions have a sour taste
2. acids change color in acid-base indicators
3. some acids react with active metals and release hydrogen gas
4. acids react with bases to produce salt and water
5. acids conduct electricity
6. strong acids completely dissociate (give up all H+ ions)
Properties of Bases
1. aq solutions taste bitter
2. bases change color of acid-base indicators
3. dilute base solutions are slippery (soap)
4. bases react with acid to produce salt and water
5. bases conduct electric current
6. strong bases completely dissociate (give up all OH- ions)
Boyles, Charles, Gay-Lussac
boyle's= pressure x volume
charles= volume/temp
gay-lussac- pressure/temp
inverse & direct
inversely- one decreases as other increases
direct- both increase/decrease
combined gas law
(pressure x volume)/ temperature
Avogadro's Law
equal volumes of equal gases at the same temperature and pressure contain equal numbers of molecules
V = kn; V = volume, k = constant, n = moles of gas
molar volume of a gas at STP
the volume occupied by one mole of a gas at STP is 22.414 Liters; this value can be used to find the mass of a gas at STP
gas law stoichiometry
The coefficients in chemical equations not only indicate molar amounts and molar ratios, but also reveal volume ratios.
ideal gas law
PV = nRT; P = pressure(atm); V = volume(L); n = number of moles; R = .0821 L x atm/Kmol; T = temperature
Graham's Law
states that the ratios of effusion of gases at the same temperature and pressure are inversely proportional to the square roots of their molar masses. ()
Reversible Reaction
a chemical reaction in which the products re-form the original reactants
the state in which a chemical reaction and the reverse chemical reactions occur at the same rate such that the concentrations of reactants and products do not change
pH and pOH
pH: the negative of the common logarithm of the hydronium ion concentration
pOH: the negative of the common logarithm of the hydroxide ion concentration
LeChatelier's principle
if a system at equilibrium is subjected to a stress, the equilibrium is shifted in the direction that tends to relieve the stress
nucleon vs. nuclide
nucleon: proton or neutron
nuclide: an atom that is identified by the number of protons and neutrons in its nucleus
Acid/base strength Ka value
Ka=acid ionization constant (represents small value)
K is constant for a specified temperature, but has a new value for each new temperature
mass defect
the difference between the mass of an atom and the sum of the masses of the atom's protons, neutrons, and electrons (the separate particles weigh more because some mass is released as energy during the formation of the nucleus)
nuclear binding energy
the energy released when a nucleus is formed from nucleons
the react of the ions that characterize acids (hydronium ions) and the ions that characterize bases (hydroxide ions) to form water molecules and salt
self ionization of water
a process in which 2 water molecules produce a hydronium ion and a hydroxide ion by transfer of a proton
band of stability
the stable nuclei cluster over a range of neutron-proton ratios
nuclear reaction
a reaction that affects the nucleus of an atom
an ionic compound that forms when a metal atom or a positive radical replaces the hydrogen of an acid
the self-ionazation of water: 2H20<-->H30+OH
the transformation of atoms of one element into atoms of a different element as a result of a nuclear reaction
the emission of energy as electromagnetic waves or as moving subatomic particles, especially high-energy particles that cause ionization
a solution that can resist changes in pH, formed by either a weak acid and its conjugate base or a weak base and its conjugate acid
pH Scale
a value that is used to express the acidity or alkalinity of a system; each whole number on the scale indicates a tenfold change in acidity; pH of 7 in neutral, a pH less than 7 is acidic, a pH more than 7 is basic
alpha vs. beta vs. gamma
alpha: a positively charged atom that is released in the disintegration of radioactive elements and that consists of 2 protons and 2 neutrons
beta: a charged electron emitted during certain types of radioactive decay
gamma: the high energy photon emitted by a nucleus during fission and radioactive decay
Conjugate Acids and Bases
conjugate acid: an acid that forms when a base gains a proton
conjugate base: a base that forms when an acid loses a proton
positron emission vs. electron
positron is a particle that has the same mass and spin state as an electron, but has a positive charge (electron is negative)
indicators (litmus, BTB, phenolphthalein)
compounds whose colors are sensitive to pH
an inner orbital electron is captures by the nucleus of its own atom
a method to determine the concentration of a substance in solution by adding a solution of known volume and concentration until the reaction is completed, which is usually indicated by a change in color
blocking radiation
shielding (sacrifice of radiation-absorbing material, usually metal, to protect a more sensitive material)
standard solution
the solution that contains the precisely known concentration of a solute
half life
the time required for half of a sample of a radioactive substance to disintegrate by radioactive decay or by natural processes
fission vs. fusion
fission: a very heavy nucleus splits into mire stable nuclei of intermediate mass
fusion: low-mass nuclei combine to form a heavier, more stable nucleus
organic chemistry
the study of chemical compounds: covalently bonded compounds containing carbon, excluding carbonates and oxides
equivalence point vs. end point
end point: point during a titration at which a marked color change occurs
equivalence point: point at which the 2 solutions used in a titration are present in chemically equivalent amounts
the branch of chemistry that is the study of the relationship between electric forces and chemical reactions
the loss of electrons, increasing the the charge of a substance in a redox reaction
the gain of electrons, reducing the charge of a substance in a redox reaction
functional groups
the portion of a molecule that is active in a chemical reaction and that determines the properties of many organic compounds
same formula, different name (example: hexane and 2 methyl pentane)
oxidizing vs. reducing agent
Oxidizing Agent: the substance that gains electrons (itself is reduced) in a redox reaction to enable the other substance to oxidize
Reducing Agent: the substance that loses electrons (itself gets reduced) in a redox reaction to enable the other substance to reduce
oxidation number
the number of electrons that must be added to or removed from an atom in a combined state to convert the atom into elemental form (neutral)
prefixes for carbon chains
1/2 reaction
the part of a reaction that involves only oxidation or reduction
alkane, alkene, alkyne
alkane: hydrocarbon characterized by a straight or branched carbon chain that contains only single bonds
alkene: hydrocarbon that contains 1+ double bonds
alkyne: hydrocarbon that contains 1+ triple bonds
anode vs. cathode
anode: red wire where oxidation occurs, positive
cathode: black wire where reduction occurs, negative
process in which an electric current is used to produce a chemical reaction, such as the decomposition of water
salt bridge
a barrier preventing the metal of one half-reaction from mixing with metal from the other half-reaction
also transfers electrons back to anode to complete the circuit