Nuclear Chemistry

Question 1

Last stable isotope

Answer 1

Pb-206 (Bismuth> is unstable, or radioactive bc larger)

Question 2

(1/2)^n

Answer 2

Fraction remaining

Question 3

n

Answer 3

of half life periods elapsed

Question 4

How can elements be made radioactive?

Answer 4

By bombarding nuclei with high energy particles

Question 5

Mass defect

Answer 5

Decease in mass produced, converted into energy

Question 6

Binding energy

Answer 6

Energy needed to break down nucleus

Question 7

Fission reaction

Answer 7

Bombs, exponential increase chain rxn of U-235+n (activated complex splits into Ba, Kr, 3n, energy)

Question 8

Fission reactor

Answer 8

Fuel, moderator, control rods, coolant to maintain temp, shielding (concrete protection, cracks)

Question 9

Isotopes for fuel

Answer 9

U-233, U-235, Pu-239

Question 10

I-131

Answer 10

Thyroid cancer

Question 11

Co-60

Answer 11

Cancer therapy

Question 12

C-14

Answer 12

Fossils/bones

Question 13

Tc-99

Answer 13

Brain tumors

Question 14

U-238

Answer 14

Dating rocks (NOT for fuel)

Question 15

Moderators that slow down/control neutrons?

Answer 15

Heavy water (2H2O or deuterium), Be, graphite

Question 16

Control rods that absorb excess neutrons?

Answer 16

Cd and B

Question 17

Coolants that maintain temperature?

Answer 17

Molten salt (good retainer of heat), 2H2O, air

Question 18

Why is it important not to dump waste into water ecosystems?

Answer 18

Warm water has higher entropy, so it has less capacity to hold dissolved oxygen (gas in liquid)

Question 19

Nuclear change when subatomic particles are absorbed or emitted by nucleus

Answer 19

Quanta of energy

Question 20

Fusion reaction

Answer 20

combining 2 light nuclei to form heavier nuclei, need high TEMP, released more ENERGY than fission, not chain rxn, problem=millions K temp (I.e. H-2+H-2>He-4+energy, mass defect, thermonuclear rxn, sun)