CHEM 121 MODULE 7 EXAM|| QUESTIONS AND ANSWERS - PORTAGE LEARNING

CHEM 121 MODULE 7 EXAM|| QUESTIONS AND ANSWERS - PORTAGE LEARNING naming covalent compounds first element is given its element name, second suffix replaced by "ide", USE GREEK PREFIXES naming ionic compounds name the metal, if the metal has an uncommon charge, indicate the charge with roman numerals, change nonmetal suffix to "ide", if polyatomic ion just name them properties of ionic compounds crystalline, hard, brittle, high melt point, insulators as solid, but conductors in solution or when melted percent composition mass of element / total mass of compound x 100 ionic which type of compound completely dissociates in water to form electrolytes? empirical formula molecular formula compound precipitate uses the simplest integers to represent the ratio of atoms in a compound shows the actual number of atoms of each element in one molecule of a when we mix solutions of soluble ionic compounds we might form an insoluble ionic compound. If so, this compound falls out of the solution as a solid what? acid any chemical that releases H+ in water base any chemical that releases OH- in water hydronium ion acids are H+ donors; H3O+ IS WHAT? arrhenius acid substance that when added to water increases the concentration of H+ ions present dissociate completely strong acids do what in water? dissociate partially water and a salt molarity weak acids do what in water? the products of an acid-base reaction will always be what? moles of solute per liter of solution (M= mol/L) increases In dilution, the number of moles does not change, but the volume what? this is the reactant in a chemical reaction that limits the amount of product limiting reactant that can be formed reactant in excess theoretical yield actual yield reactant in which some of it will remain at the end of the reaction max amount of product that can be obtained, that YOU calculate amount of product that we obtain in an experiment percent yield % = actual / theoretical x 100 heat the amount of energy that can be transferred from one object to another due to a temperature difference temperature measure of the average kinetic energy of particles exothermic system releases heat endothermic system absorbs heat titrations known amount enthalpy used to find the molarity of solutions, find the moles of solute by reaction with a the heat of reaction at constant pressure, delta H energy = q + w (heat + work) specific heat (c), the amount of energy needed to raise the temperature of one gram of a substance one degree C heat q= m x c x deltaT calorie amount of heat needed to raise the temperature of one gram of water by one degree celcius calorimeters this is used to find energy in chemical reactions, coffee cup/bomb hess's law of heat summation If the equation for a reaction can be written as 2 or more thermochemical equations, then the enthalpy change for the reaction equals the sum of the enthalpies of those equations standard enthalpy of formation bomb calorimeter = SUM deltaHf of products - SUM deltaHf of reactants q = Ccal x deltaT heat capacity C = m x c (m= mass c= specific heat) light a form of electromagnetic radiation, composed of two perpendicular oscillating waves speed of light 3.00 x 10^8 m/s wavelength amplitude frequency distance between two peaks of a wave (lambda) height of the wave (nu), number of waves passing per unit of time (units: Hertz) frequency equation v= speed / wavelength energy of a photon equation E= hv, E= hc/lambda planck's constant 6.626 x 10^/34 j.s bohr this man said that electrons in atoms can only have certain energies; they are quantized photoelectric effect de broglie light as particles (photons) this man proposed that particles could have wave-like character, lambda= h/mv orbital region of space where an electron in an atom is most likely to be found principal quantum number n=1,2,3,..... n, divides an atom into shells angular momentum quantum number l, divides each shell into subshells s (l=0),p (l=1),d (l=2),f (l=3) magnetic quantum number ml, divides each subshell into orbitals, 2l+1 shells in each orbital, can be anywhere from -l to +l electron configuration shows the distribution of electrons among the shells, subshells, and orbitals of an atom valence electrons electrons in the outermost shell core electrons electrons in the inner shells paramagnetic contains unpaired electrons diamagnetic contains paired electrons ionization energy phase atom electron affinity amount of energy required to remove an electron from an isolated, gas amount of energy released when a free, gas phase atom gains an electron crystal lattice this forms when ionic compounds become solid; the ions are stabilized by being surrounded by opposite charges. Also energy is released. octet rule when atoms bond, they tend to gain, lose, or share electrons to result in eight valence electrons electronegativity the tendency of an atom in a molecule to attract electrons toward itself polar covalent bond if two atoms of different electronegativity share electrons, this results pure or nonpolar bond bond where electrons are equally shared small electronegativity difference 0-0.4 intermediate electronegativity difference large electronegativity difference 2.0 + 0.4-2.0 resonance structures lewis structures that differ only in the placement of electrons are called what? resonance hybrid combination of all possible resonance structures endo is breaking bonds endo or exo exo is forming bonds endo or exo deltaH rxn from bond energies deltaH= SUM of energies broken - SUM of formed hybridization when orbitals are close enough in energy, they can combine to form the same number of new orbitals that are intermediate in energy valence bond theory This theory states that atoms share valence electrons to form bonds. Also, to comply with the octet rule, sometimes atoms need to hybridize to have enough unpaired electrons. gas kinetic molecular theory gases consist of many many particles that are really really small and very far apart. The particles move in random straight lines that occasionally collide pressure = force/area units of