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Drill:. Calculate the solubility of MgF 2 in 0.10 M KF. K sp MgF 2 = 6.4 x 10 -9. 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. Nuclear Chemistry.
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Drill: • 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 • 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 (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
AP CHM HW • Read: Chapter 19 • Problems: 5 & 7 • Page: 552
CHM II HW • Read: Chapter 26 • Problems: 31 & 35 • Page: 1036
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 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
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
Drill: 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
AP CHM HW • 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
Drill: • 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 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: • DE = Dmc2