Ap Chemistry: Redox Ad Electrochem

Front 1

Rules of oxidation numbers

Back 1

1. Atoms of pure elements are 0.
2. Oxidation #'s for monatomic ions are equal to charge of the ion.
3. Fluorine is always -1 with all other elements.
4. Cl, Br, and I are always -1 in compounds except when combined with oxygen or fluorine.
5. H is +1 and O is -2 in most compounds.
6. Sum of the oxidation $'s for atoms of neutral compound must be 0 and in polyatomic ion must be the charge of the ion.

Front 2

What is the difference between oxidation and reduction?

Back 2

Oxidation is the increase in oxidation # and the loss of electrons while reduction is the decrease of oxidation # and gain of electrons.

Front 3

Define oxidizing agent and reducing agent.

Back 3

Oxidizing agent is what is being reduced and reducing agent is what is being oxidized.

Front 4

Steps of balancing redox reactions

Back 4

1. Write 2 half-reactions.
2. Balance all atoms except for oxygen and hydrogen
3. Balance oxygen by adding H20 for each oxygen needed.
4.Balance hydrogen atoms by adding H+ ions.
5. Balance charges by adding proper number of electrons.
6. Multiply each half reaction by the appropriate number so that the electrons will cancel. Add the 2 half-reactions and cancel common ions and molecules.

Front 5

What is the difference between balancing in a basic solution and acidic solution?

Back 5

Instead of using H+ in basic solutions, use OH- to cancel the hydrogens.

Front 6

Balance acid solution

Cu + NO3- -> NO2 + Cu2+

Back 6

Cu + 2 NO3- + 4H+ -> 2NO2 + Cu2+

Front 7

Balance basic solution

MnO2 + ClO3- -> MnO4- + Cl-

Back 7

2MnO2 + 2OH- + ClO3- 2MnO4- + Cl- + H2O

Front 8

Define cathode and anode

Back 8

Reduction occurs at the cathode and oxidation occurs at the anode.

Front 9

What is the difference between electrolytic cells and galvanic cells?

Back 9

In electrolytic cells, electric energy must be supplied in order to create the flow of electrons and thus, it is nonspontaneous while in galvanic cells, no energy is needed to start the reaction.

Front 10

Which way do electrons flow in electrolytic cells and in galvanic cells?

Back 10

Electrolytic: anode -> cathode

Galvanic: cathod -> anode

Front 11

What is electrolysis?

Back 11

It is a nonspontaneous chemical reaction (electrolytic) where 2 electrods are immersed in a electrically condctive sample and electricity is applied applied until electrons flow.

Front 12

What is the equation to find the standard cell voltage?

Back 12

Ecell = Ecathode - Eanode

All must be at standard conditions.

Front 13

Using the voltage, when is a reaction spontaneous and when is it nonspontaneous?

Back 13

Nonspontaeous when the E cell value is negative and spontaneous when it is positive.

Front 14

Are batteries Galvanic or electrolytic?

Back 14

Galvanic, they convert chemical energy into electrical energy.

Front 15

What is the anode and the cathode in this Galvanic cell? Which way does the electron flow ?

Back 15

Zn - anode
Ni - cathode

Electrons flow Zn -> Ni