Drill: Calculate the solubility of MgF 2 in 0.10 M KF. K sp MgF 2 = 6.4 x 10 -9

Drill: A statue is electroplated at the cathode using a silver anode in aqueous AgNO 3. Calculate the current required to plate 10.8 g of silver in 5.0 minutes.

Review & Collect Drill & HW

CHM II HW Review PP-29 Work the attached problem & turn it in tomorrow.

Drill: Calculate the volume of Cl 2 formed at 27 o C 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 4 He or 2 4  Beta: -1 0 e or –1 0  Gamma: 0 0  Positron: +1 0 e K-electron: -1 0 e

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

Review & Collect Drill & HW

CHM II HW Review PP-29 Work the attached problem & turn it in tomorrow.

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: 2 4 He or 2 4  Beta: -1 0 e or –1 0  Gamma: 0 0 

Nuclear Symbols Neutron 0 1 n Proton 1 1 p Electron -1 0 e

Transmutation Rxns  emission of Pm-142  bombardment of Th-231

Transmutation Rxns  emission of  U   followed by two separate  emissions:

Transmutation Rxns  bombardment of Th  followed 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 U  followed by two separate  emission:

Review Drill & Check HW

CHM II HW Review PP-29 Complete the attached assignment & turn it in tomorrow.

Next Test on Friday

Nuclear Power

Nuclear Fission U-235 is the only fissable isotope of uranium 0.71 % of uranium is U % 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 = k  X/  t ln(X i /X f ) = kt 1/2 k = 0.693/t 1/2 t 1/2 = half-life

1st Order Age Dating Formula ln(X i /X f )t 1/ t =

Calculate the age of a skeleton found with % C-14 when atmospheric C-14 = 1.00 %. t 1/2 C-14 = 5730 yr

Calculate the age of a tooth found with % C-14 when atmospheric C-14 = 1.00 %. t 1/2 C-14 = 5730

Drill: Predict the products in each step when Boron-12 goes through  bombardment followed by  emission.

Review & Collect Drill & HW

CHM II HW Review PP-29 Complete the attached assignment & turn it in tomorrow.

Test Friday

Predict the products in each step when Uranium-234 goes through 5 straight  emissions.

Calculate the age of a bone found with % C-14 when atmospheric C- 14 = 1.00 %. t 1/2 C-14 = 5730

Mass-Energy Relations  E =  mc 2

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 =  mc 2

Binding Energy The energy that holds a nucleus together corresponds to  m of nucleus

In an atomic bomb, kg of U-235 ( ) is split into Ba-143 ( ) + 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

Review & Collect Drill & HW

Test Tomorrow

Test Review

A fossil contained 3.125% of its original carbon-14. Determine its age. t 1/2 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(X i /X f )t 1/ t =

Calculate the age of a bone found with % C-14 when atmospheric C-14 = 1.00 %. t 1/2 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 ZnCl 2(aq) & CaBr 2(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 Al 2 O 3 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.