Define oxidation and reduction in terms of electron loss and gain.
Oxidation is the loss of electrons while reduction is the gain of electrons.
100
What is the purpose of half equations?
To separate an equation into reduction and oxidation equations.
100
Why do reactive metals serve as stronger reducing agents?
Because they lose their electrons more readily.
100
What is a voltaic cell?
A cell that separates two half equations into two half cells and allowing electrons to flow between them only through an external circuit. It harnesses the energy released in redox reaction as electrical energy.
100
What is an electrolyte?
A liquid that conducts electricity and undergoes chemical change as a result (typically molten ionic compounds, or aqueous solutions of ionic compounds).
200
If the oxidation number of an element increases has the element been oxidized or reduced?
Oxidized
200
What is added to either side of a half equation in order to balance it?
Electrons
200
What is the purpose of the reactivity series?
To determine the feasibility of a reaction.
200
In general, the more reactive a metal, the more__________ its electrode potential in its half cell
negative
200
Where does the redox reaction occur in electrolytic cells?
At the electrodes.
300
What is the oxidation number of S in H2SO4?
+6
300
Write the half equations for Zn + Cu (2+) --> Zn (2+) + Cu
Zn --> Zn (2+) + 2e-
Cu (2+) + 2e- --> Cu
300
AgCl2 + 2Zn --> 2ZnCl + Ag Based on this equation is Zinc or Silver higher on the reactivity series?
Zinc
300
Oxidation occurs at the ___________ and reduction occurs at the _____________
anode, cathode
300
How is an electrolytic cell different from a voltaic cell (think energy)?
A voltaic cell takes the energy of a spontaneous redox reaction and harnesses it to produce electric voltage, while an electrolytic cell takes energy from an external source of voltage to bring about a redox reaction (they are opposites).
400
Name three elements whose oxidation number can differ according to compounds other than transition elements.
O, H, Cl, N, P, S, Sn, Pb
400
What is the definition of an oxidizing agent (2 parts).
The reactant that is being reduced and accepts electrons.
400
What temperature must Ag be to more reactive on the activity series than Zn?
Temperature has no effect.
400
Electrons always flow in the external circuit from _________ to __________
anode to cathode
400
Explain the half reactions of the electrolysis of a molten salt (NaCl).
2Cl- ---> Cl2 + 2e- , 2Na+ + 2e- ---> 2Na, the second equation is doubled because there must be and equal number of electrons released at the anode as are taken up at the cathode.
500
List 3 rules to identify the oxidation number of any element or compound.
The sum of the oxidation number of all atoms in a neutral compound must equal 0. Atoms in elemental state have an oxidation number of zero. The oxidation number of simple ions is equivalent to the charge of the ion.
500
Identify the reducing and oxidizing agents in CH4 + 2O2 --> CO2 + 2H2O
O2 is the oxidizing agent and CH4 is the reducing agent.
500
This question is double points!
Pb + X(2+) --> Pb(2+) + X,
Q + X(2+) --> no reaction,
Pb + Q(2+) --> Pb(2+) + Q
Arrange the metals Pb, Q, and X in order from least reactive to most reactive. Lets see who looked at the AP packet.
Pb, X, Q
500
What two things that are needed to make connection between the half cells