CHAPTER 10 Nuclear Chemistry

1
CHAPTER 10 Nuclear Chemistry

• Radioactivity

2
Definitions

• Radioactivity
• emission of high-energy radiation from the
  nucleus of an atom
• Nuclide
• nucleus of an isotope

3
Types of Radiation

• Alpha (?)
• helium nucleus

paper
2

• Beta-minus (?)
• electron

lead
1-

• Gamma (?)
• high-energy photon

concrete
0
4
Nuclear Decay

• Why nuclides decay
• to obtain a stable ratio of neutrons to protons

Stable
Unstable (radioactive)
5
Nuclear Decay
TRANSMUTATION

• Alpha Emission

• Beta Emission

6
Half-life

• Half-life (t½)
• time it takes for half of the nuclides in a
  sample to decay

7
Half-life Problem

• How much of a 20-g sample of sodium-24 would
  remain after decaying for 30 hours? Sodium-24
  has a half-life of 15 hours.

GIVEN total time 30 hours t1/2 15
hours original mass 20 g
WORK number of half-lives 2 20 g 2 10 g
(1 half-life) 10 g 2 5 g (2
half-lives) 5 g of 24Na would remain.
8
F ission

• splitting a nucleus into two or more smaller
  nuclei
• some mass is converted to large amounts of energy

9
F ission

• chain reaction - self-feeding reaction

10
Fusion

• combining of two nuclei to form one nucleus of
  larger mass
• produces even more energy than fission
• occurs naturally in stars

11
Nuclear Power

• Fission Reactors

12
Nuclear Power

• Fission Reactors

13
Nuclear Power

• Fusion Reactors (not yet sustainable)

14
Nuclear Power

• Fusion Reactors (not yet sustainable)

National Spherical Torus Experiment
Tokamak Fusion Test Reactor Princeton University
15
Nuclear Power
FISSION
FUSION
vs.

• 235U is limited
• danger of meltdown
• toxic waste
• thermal pollution

• Hydrogen is abundant
• no danger of meltdown
• no toxic waste
• not yet sustainable

16
Others

• Irradiated Food
• Radioactive Dating
• Nuclear Medicine
• Nuclear Weapons