APCHEM Unit 2

LEO

Loose Election Oxidize (get more positive)

GER

Gain electrons Reduced (get more negative)

What happens if the E cell > 0 and Delta G is < 0

Spontaneous Reaction

What happens if E cell < 0 and Delta G is > 0

Non-spontaneous reaction

What is E cell

E red + E ox

What happens at the Anode?

Oxidiation

What happens at the Cathode?

Reduction

If you’re using KNO3 as your salt bridge, where does NO3- go?

To the Anode side.

If you’re using KNO3 as your salt bridge, where does K+ go?

To the Cathode side

In reduction reactions where does e- go?

On the reactant side

In oxidation reactions where does e- go?

On the product side.

How do you balance O in redox problems?

With H2O

How do you balance H in redox reactions?

With H+

What equation do you use if it aks you about amps and time?

q ( c )= I (amps) x t (sec)

For every 96485 c there is ___?

1 mol e-

Electrons travel in what way?

From anode to cathode

What does a higher e-cell value mean?

Better at being reduced

The ion being reduced will what?

Gain mass over time bc X +_ is being reduced to X (s)

The ion being oxidized will what?

Increase in concentration. X (s) oxidizes into X +_

What is true about the E cell and Delta G when the battery dies?

E cell and Delta G will be 0. The electrons will be travelling in equal and opposite directions

What is K

Equilibrium Constant

What shouldn’t be incluided in Kc

Solids and Liquids

How should you write Kc

[Products]^ Coeff / [Reactants] ^ Coeff

K < 1 means what?

Reactants favored, Delta G > 0, E cell < 0

K > 1 means what?

Product favored, Delta G < 0, E cell > 0

What is Q

The REACTION quotient

What happens when Q > K

Reaction is product heavy, the reverse reaction will speed up until equilibrium is achieved

What happens when Q < K

Reaction is reactant heavy, the forward reaction will speed up until equilibrium is achieved

What is Partial Pressure?

Pa + Pb = Ptotal

How do you write Kp

(Pproducts) ^ Coeff / (Preactants) ^ Coeff

In an equilibrium graph how do you know what the product is?

The one that starts at 0

K only changes with what?

Temperature

What unit goes with K?

None, K is a unit-less value

In graphs how do you find the Coeff?

The slope (if its going down or up by x2 then the coeff is 2)

What is Gibbs free energy equation?

Delta G = -(R)(Temp)ln(K)

What is the re-arranged equation when you need to find Keq?

-(delta G) / (R)(Temp) e (press e last)

When its asks you to fill in the missing data points for a graph how do you do it (PS 7.1 Q4c)

t=0 # - t=__ # to find mol used then find the M of that.

How to go from J to KJ

Multiply by exponent -3 (move decimal 3 places to the left)

When finding the concentration of the reactants what mol do you use to find the M? (PS 7.1 Q9c)

Mol of excess/leftover