Q 12/13

thermodynamically favorable reactions have a….

negative delta G

reactions with ____ and ____ are always thermodynamically favorable (enthalpy driven & entropy driven)

negative delta H and positive delta S

reactions that increase the number of moles of gas have a…..

positive delta S

if delta G is negative, then….

Keq>1

____ and ____ are usually not given in the same units

delta H and delta S

to make sure the delta H and delta S units match up, use the formula….

delta G = (delta H) - (T)(delta S)

at equilibrium, delta G equals….

0

when using delta G = -(R)(T)(lnK), the value for R is ____, so the answer will be in ____

8.314 J/molK, Joules

if a reaction with a negative delta G does not proceed at a measurable rate, they are said to be under….

kinetic control

____ is a common reason for a process to be under kinetic control

high activation energy

H oxidation number

+1 (except in a hydride when it is -1)

O oxidation number

-2 (except in a peroxide when it is -1)

LEO

loses electrons oxidized

GER

gains electrons reduction

oxidation always occurs at the ____ in both a battery and an electrolytic cell

anode

electrons in a battery flow from….

anode (-) to cathode (+)

in a salt bridge, cations flow to the ____ and anions flow to the ____

cathode, anode

while a battery is discharged, the ____ gains mass and the ____ loses mass

cathode, anode

if you reverse a reaction, E cell….

changes sign

if you double a reaction, E cell….

does not change

E cell equals….

E nott red GER - E nott red LEO

the other way to calculate E not cell is….

E nott reduction + E nott oxidation, but that involves reversing and changing the sign of a reaction

the half reaction with a more positive E nott red is the reaction that takes place at the….

cathode (GER)

when adding two half reactions together….

the electrons must cancel out

knife equation

delta G = -(n)(F)(Enott)

if delta G not is negative, then E nott cell is….

positive

n in the knife equation is….

number of electrons transferred

if Q increases, then the voltage (E nott cell) of the battery….

decreases

electroplating/electrolysis calculations

grams = (molar mass of the metal)(amps)(seconds)/(n)(F) also written as g=(MM)(I)(t)/nF