A resistor and a 295-mH inductor are connected in series with an ac generator with an rms voltage of 20.0 V and a frequency of 60.0 Hz. What is the rms current in this circuit?
GEN CHEM II EXAM 2 – STUDY GUIDE Chapter 15 – Chemical Equilibrium Equilibrium Reaction proceeds simultaneously in both directions (dynamic equilibrium). Forward rate = Reverse rate Denoted by a double arrow Equilibrium Constant in terms of concentration in M (K ): HCl H + Cl - + − c = [ ][ ]  [ ][ ] =  For all non-equilibrium concentrations. If Q > K, shift to left If Q < K, shift to right If Q = K, equilibrium If K ic a big number more products If K is a small number more reactants c General: aA bB =  , coefficients are exponents in equilibrium constant  expression. K oc reverse = 1/K ofcforward. Equilibrium concentrations of liquid and solid reactants or products is considered to be 1. Equilibrium Constant in terms of pressure (K p K =pK (RTc delta n o, delta n of gas = final (products) gas moles – initial (reactants) gas moles. Used for reactions in gas phase (can also use K )c All others rules same as that of K . c Calculating K c ex. H2(g) + I2(g) 2HI(g), [H2] initial = 0.100 M [2 ] = 0.100 M [2 ] eq = 0.0200 M RICE Table: Reaction H2 I2 2HI Initial 0.100 0.100 0 Change -x -x 2x Equilibrium 0.100+x 0.100-x = 0.0200 2x 0.100-x = 0.0200 x = 0.08, 2x = 0.16 2 (0.16) 2 = = = 64 2 ]2 (0.0200)(0.0200) RICE table can also be used to calculate concentration, given K c Can also be used for K ppressure). Chapter 16 – Acids, Bases and Salts Bronsted Acids and Bases Acid/base reaction – proton transfer. Acid – proton donor. Base – proton acceptor. Conjugate base – what remains of the acid after it donates a proton. Conjugate acid – species formed when the base accepts a proton. Properties of water Amphoteric – can act as either an acid or base. Auto ionization – water can ionize by itself. -14 o + - K (won product constant for water) = 1.0 x 10 at 25 C, K w [H ][OH ] The pH scale + + - pH = -log[H ] or –log[H ], pOH = -log[OH ] pH < 7, acidic; pH = 7, neutral (water); pH > 7, basic pH + pOH = pK = 14w Strong Acids and Bases Ionize or disassociate 100% More ionization = stronger acid/base Oxoacids: has atleast one oxygen, hydrogen, and a central nonmetal X Same number of oxygen, different X Electronegativity inc. strength of acid inc. Carboxylic acid (contains R group) Electronegativity of R inc. strength of acid inc. Same X, different number of oxygen Number of O inc. electronegativity inc. strength inc. Different X, different number of oxygen Stronger acid weaker the conjugate base Binary Acid: one H and one nonmetal Nonmetal X Left to right across periodic table stronger acid Top to bottom down periodic table stronger acid Weak acids: ionize only to a certain extent Depends on concentration of acid and equilibrium constant for ionization (K ). a + - HA(aq) + H O(l2 H 3 (aq) + A (aq) +][ ]  Larger K astronger acid pK a -logK a Weak bases: similar treatment as for weak acids - + K hbs [OH ] instead of [H ] Conjugate Acid-Base pairs K Ka= b w pK + aK = pKb= 14 aw 25 C o As K geta larger, K getb smaller – stronger the acid, weaker the conjugate base! AND VICE-VERSA Calculating K andaK usingbRICE table: make approximation (x = 0) only if [HA]initial/K =agreater than 1000 Diprotic and Polyprotic Acids + + + K >>a1 [H ]a2 total [H ] 1st+ [H ] 2nd [H ] 1st> [H ]+ 2nd [H ] total [H ]1st Acid- Base Properties of Salts: salts dissociate into cations and anions in solution Cations + Conjugate acid of weak base weak acid, ex. NH 4 Hydrated metals act like weak acids Group IA and IIA metals except Be – non acids(charge density too low) Charge inc. metal size dec. acidity inc. Anions Conjugate bases of weak acids weak bases If both anion and cation are acids/bases pH depends on relative strength of conjugate acid and base When K > b , tha solution is basic When K < b , tha solution is acidic When K = b , tha solution is neutral Acid-base properties of oxides Alkali metal oxides and alkali earth metal oxides (except BeO) are basic. Nonmetal oxides tend to be acidic Be(OH) , Al2OH) , Sn(3H) , Pb(OH2 , Cr(OH)2, Cu(OH) ,3Zn(OH) , a2d Cd(OH) ,2are 2 amphoteric and insoluble in water. React with acids and bases Lewis Acids and Bases Lewis base: electron pair donor Must contain one or more lone pairs of e - Lewis acid: electron pair acceptor Contains incomplete valence shell or multiple bonds that can shift to make room for lone pair. Lewis acid-base reaction: transfer of electron pair (formation of coordinate covalent bond) Lewis concepts include all Arrhenius and Bronsted acids/bases