Electrochemistry and Nuclear Chemistry Flashcards
oxidation
- increase bonds to O
- lose electrons
- lose bonds to hydrogen
reduction
- lose bonds to O
- gain electrons
- gain bonds to hydrogen
the oxidation state of any element in its standard state
0
ox state of group 1 metals
+1
ox state of group 2 metals
+2
ox state of fluorine
-1
ox state of hydrogen
- +1 when bonded to something more electronegative than carbon
- -1 when bonded to something less electronegative than carbon
- 0 when bonded to carbon
ox state of oxygen
-2
ox state of halogens
-1
ox state of oxygen family
- 2
reducing agents
- compounds like cause others to gain electrons
- they like to get oxidized in the process
- neutral metals = low EN atoms
- LiAlH4
- NaBH4
oxidizing agents
- compounds that cause others to lose electrons
- they like to get reduced in the process
- neutral nonmetals
- MNO4
- Cro3
+E
- indicates a spontaneous reaction as written
-E
- indicates a nonspontaneous reaction as written
when you reverse the reaction
- flip the sign of E
more negative in the reduction table
- means less likely to do the written reaction
- less likely to be reduced
- reducing agents because they want to be oxidized
more positive in reduction table
- more likely to do the written reaction
- more likely to be reduced
- oxidizing agents because they want to be reduced.
do the coefficients affect the value of E cell?
NO!
- just do Hess’s law except never multiply by coefficients
relationship between free energy and E_cell
- inverse relationship
formula for free energy and E_cell
ΔG = -nFE_cell
F = 96500
Faraday’s Law
I = nF/t
Galvanic cell
- spontaneous redox (+Ecell)
- need 2 beakers and a salt bridge
Electrolytic cell
- non-spontaneous redox (-Ecell)
- has a battery to make it run
- Don’t need two beakers
what occurs at the anode
- oxidation
what occurs at the cathode
- reduction
anode of a galvanic cell
- where oxidation occurs
- (-) terminal
- nonspontaneous reduction E-
cathode of a galvanic cell
- where reduction occurs
- (+) terminal
- spontaneous reduction E+
conduction wire
- flows from anode to cathode
- current flows opposite
salt bridge
- completes circuit by balancing charge
cut wire
- instant death
cut salt bridge
- slow death
- capacitor
run out of stuff
- equilibrium
increase temperature
- lose solution to evaporation
decrease temperature
- too viscous
will you ever see a metal with a negative charge on the MCAT?
- no!
what does iron do?
- oxidize
- spontaneous corruption
what does copper do?
- reduce
- spontaneous plating
where does solid metal form
- always at the cathode
where does H2 form
- always at the cathode
where does O2 form?
- always at the anode
anode in an electrolytic cell
- where oxidation occurs
- (+) terminal
cathode in electrolytic cell
- where reduction occurs
- (-) terminal
Nernst equation
- a cell in equilibrium has a non-zero standard cell potential
E=E^o - RT/nF lnQ
- a cell in equilibrium has an actual cell potential equal to zero
E^o = RT/nF lnQ
Iodometry
- a redox titration where the consumption of iodine indicates the titration end point.
alpha decay
- Helium emitted from nucleus
4
2 He
- Z decreases by 2
- atoms with very large nuclei
- least dangerous type
beta decay
- electron emitted
0
-1 e-
- nuclei with high ratio of neutrons to protons
- more dangerous (have a higher penetrating ability) than alpha particles
positron emission
0
1 e+ released by nucleus
- nuclei with high ratios of protons to neutrons
electron capture
0
-1 e absorbed by nucleus
- Z decrease by 1
- nuclei with high proton to neutron ratios
gamma decay
0
0 y emitted by nucleus
- Z stays the same
- nuclei in an excited state
- accompanies most nuclear reactions
- most dangerous type of radiation with greatest penetrating ability
