Drill:•Calculate the solubility of MgF2 in 0.10 M KF.
•Ksp MgF2 = 6.4 x 10-9
Drill: A statue is electroplated at the cathode
using a silver anode in aqueous AgNO3. Calculate
the current required to plate 10.8 g of silver in 5.0
minutes.
Drill: Calculate the volume of Cl2 formed at 27oC under 75 kPa when xs molten NaCl is electrolyzed with
96.5 mA for 5.0 mins.
Nuclear Chemistry•The study of
reactions that take place in the nuclei
of atoms
Chemical Reactions•In normal chemical
reactions, only the electrons are
involved
Radioactive Nuclei
•Nuclei that spontaneously
decompose
Isotopes•Elements with the
same atomic number, but different mass
number
Isotopes•Elements with =
numbers of protons, but numbers of
neutrons
Isotopes•All elements have
at least one radioactive isotope
Nuclear Radiation•The emission of
particles & rays from spontaneously
decomposing nuclei
Modes of Decay•Alpha emission
•Beta emission
•Gamma emission
•Positron emission
•K-electron capture
Alpha Particle ()•Helium nucleus
•2 protons & 2 neutrons
•mass = 4 amu
•charge = +2
•Penetration power: small
Beta Particle ()•High speed electron
•1 electron
•mass = 1/1836 amu
•charge = -1• Penetration power: medium
Gamma Ray ()•High energy photon
•Electromagnetic wave
•mass = 0
•charge = 0
•Penetration power: great
Positron ()•Positive electron
•1 positive electron
•mass = 1/1836 amu
•charge = +1• Penetration power: medium
K-capture•The capture of an inner
level e- by the nucleus
•1 electron
•mass = 1/1836 amu
•charge = -1
Nuclear Symbol•Alpha: 2
4He or 24
•Beta: -10e or –1
0
•Gamma: 0 0
•Positron: +10e
•K-electron: -10e
Fission•The splitting of a nucleus into smaller nuclei involving the
release of energy
Fusion•The combining of smaller
nuclei into a larger nucleus involving the
release of energy
Drill:•Name &
describe 3 types of radiation
Fission•The splitting of a nucleus into smaller nuclei involving the
release of energy
Fusion•The combining of smaller nuclei into a larger one involving the release of energy
Transmutation Rxns
•Nuclear reactions in which one
element is changed into another
Transmutation Rxns•Reactions in
which the nucleus of an atom is
changed
Transmutation Rxns
•Both fission & fusion are
examples of transmutation rxns
Transmutation Rxns•Can occur through
emission of or bombardment by
particles
Nuclear Symbol
•Alpha: 24He or
24
•Beta: -10e or –1
0
•Gamma: 0 0
Nuclear SymbolsNeutron
01n
Proton11p
Electron-1
0e
Transmutation Rxns emission of Pm-142
bombardment of Th-231
Transmutation Rxns emission
ofUfollowed by two
separate emissions:
Transmutation Rxns bombardment ofThfollow
ed by two separate emission:
Predict Products
emission of O-18 followed by a emission:
Predict Products absorption by V-
45 followed by neutron emission then emission
Predict Products neutron bombardment of Ta-182 followed by
emission then emission
Drill: Predict Prod Neutron absorption by Ufollowed by two separate
emission:
Nuclear Fission• U-235 is the only fissable
isotope of uranium
• 0.71 % of uranium is U-235
• 99.28 % of uranium is U-238
Nuclear Fission• Chain reaction can occur only
when it reaches critical mass
• The percentage of U-235 in uranium is too low to form a chain reaction
Nuclear Fission• To run a power plant, the U-235
needs to be enriched to ~ 2%
• To make a bomb, the U-235 needs to be enriched to > 70%
Nuclear Fission• To create a chain reaction,
the U-235 % must be increased (enriched) greatly
• Ultra-centrifugation
Nuclear Fission Bomb
Decay Rate
The rate at which radioactive nuclei
break down
Half-Life The time it takes for
50 % of the radioactive nuclei to
decompose
Decay Rate Rate = kX/t
ln(Xi/Xf) = kt1/2
k = 0.693/t1/2
t1/2 = half-life
1st Order Age Dating Formula
ln(Xi/Xf)t1/2
0.693t =
Calculate the age of a skeleton found with 0.125 % C-14 when atmospheric C-14 =
1.00 %.
t1/2 C-14 = 5730 yr
Calculate the age of a tooth found with
0.00132 % C-14 when atmospheric C-14 =
1.00 %.
t1/2 C-14 = 5730
Drill:Predict the products in
each step when
Boron-12 goes through bombardment followed
by emission.
Predict the products in each step when
Uranium-234 goes through 5 straight
emissions.
Calculate the age of a bone found with
0.000010 % C-14 when atmospheric C-14 = 1.00 %. t1/2 C-14
= 5730
Mass-Energy Relations
E = mc2
Nuclear Fact The mass of any nucleus
is different than the sum of the masses of its protons & neutrons
Nuclear Fact The energy
corresponding to the mass difference can
be solved using:E = mc2
Binding Energy The energy that holds
a nucleus together corresponds to m of
nucleus
In an atomic bomb, 40.00 kg of U-235 (235.401) is split
into Ba-143 (143.223) + Kr-89 (89.335) + 2
neutrons (1.014). A) Calculate the energy released. B)
Calculate the wavelength of the ray
Drill: Show neutron bombardment of
Ra-223 followed by 3 alpha emissions
•A fossil contained 3.125% of its original carbon-14. Determine its age.
•t1/2 for C-14 = 5730 yrs
Know the radioactive
particles & their characteristics.
Alpha ()Beta ()
Gamma ()
Know how to balance
transmutation reactions
Show the intermediates and the final isotope of alpha bombardment of
Xe-136 followed by two separate beta emissions.
Know how to perform age dating
ln(Xi/Xf)t1/2
0.693t =
Calculate the age of a bone found with
0.000010 % C-14
when atmospheric
C-14 = 1.00 %.
t1/2 C-14 = 5730
Know How to Determine
Reactions in an Electrolytic Cell
2.0 volts is applied to a system through 2 platinum electrodes in an aqueous
solution containing ZnCl2(aq) & CaBr2(aq).
Calculate: anode, cathode,
& total rxns & voltages.
Know how to make
electroplating calculations.
Charge (mass) =current x time
coul = amp x sec
q = It
Saul’s Rule
nFm = MWIt
Calculate the mass of Al purified from
Al2O3 using a current of 96.5 MA
for 5.0 hrs.
Calculate the time required to plate
1.08 g of silver onto a cathode using a
current of 965 mA.