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Drill:

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- Calculate the solubility of MgF2 in 0.10 M KF.
- KspMgF2 = 6.4 x 10-9

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

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

- A nucleus that spontaneously decomposes

- Elements with the same atomic number, but different mass number

Isotopes

- Elements with = numbers of protons, but numbers of neutrons

- All elements have at least one radioactive isotope

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 (a)

- Helium nucleus
- 2 protons & 2 neutrons
- mass = 4 amu
- charge = +2
- Penetration power: small

Beta Particle (b)

- High speed electron
- 1 electron
- mass = 1/1836 amu
- charge = -1
- Penetration power: medium

Gamma Ray (g)

- High energy photon
- Electromagnetic wave
- mass = 0
- charge = 0
- Penetration power: great

Positron (p)

- 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:24Heor24a
- Beta: -10eor –10b
- Gamma: 0 0
- Positron: +10e
- K-electron: -10e

Fission

- The splitting of a nucleus into smaller nuclei involving the release of energy

- Name five types of radiation

Drill:

- Name 3 common types of radiation

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 radioactive particles

Transmutation Rxns

- b emission of Pm-142
- a bombardment of Th-231

- Read: Chapter 19
- Problems: 5 & 7
- Page: 552

CHM II HW

- Read: Chapter 26
- Problems: 31 & 35
- Page: 1036

Transmutation Rxns

- a emission ofU-238 followed by two separate b emissions:

Transmutation Rxns

- a bombardment ofTh-235 followed by two separate b emission:

Drill: Predict Prod

- Neutron absorption by U-238 followed by two separate b emission:

Drill: Predict Products

- a emission of O-18 followed by a
- b emission:

Predict Products

- K-capture by V-45 followed by neutron emission then a emission

Predict Products

- b absorption by V-45 followed by neutron emission then a emission

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 = kDX/Dt
- ln(Xi/Xf) = kt1/2
- k = 0.693/t1/2
- t1/2 = half-life

Predict the products in each step when

Boron-12 goes through a bombardment followed by b emission.

1st Order Age Dating Formula

- ln(Xi/Xf)t1/2
- 0.693

t =

- Calculate the age of a skeleton found with 0.125 % C-14 when atmospheric C-14 = 1.00 %.
- t1/2 C-14 = 5720 yr

- Calculate the age of a tooth found with 0.00132 % C-14 when atmospheric C-14 = 1.00 %. t1/2 C-14 = 5720

- Read: Chapter 19
- Problems: 26 & 27
- Page: 553

CHM II HW

- Read: Chapter 26
- Problems: 53 & 54
- Page: 1037

- Calculate the age of a bone found with 0.000300 % C-14 when atmospheric C-14 = 1.00 %. t1/2 C-14 = 5720

- A fossil contained 3.125% of its original carbon-14. Determine its age.
- t1/2 for C-14 = 5720 yrs

Mass-Energy Relations

- DE = Dmc2

Nuclear Fact

- The mass of any nuclei 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:
- DE = Dmc2

Binding Energy

- The energy that holds a nucleus together corresponds to Dm 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 g ray

Drill: Show neutron bombardment of Ra-223 followed by 3 alpha emissions