Unit 3 - Nuclear Chemistry - Energy in Nuclear Reactions, Fission and Fusion

Question 1

Energy in Nuclear Reactions compared to Energy in Chemical Reactions

Answer 1

NUCLEAR HAS MUCH MUCH MORE ENERGY THAN CHEMICAL REACTION

Question 2

What is Einstein’s equation? (6)
Equation, What it Stands for, Nuclear vs. Chemical

Answer 2

1. E = mc2
2. E = Energy
3. m = Mass
4. c = Speed of Light
5. A small amount of mass is converted to a LOT of energy in nuclear reactions
6. Mass converted to energy is minimal in chemical reactions

Question 3

What are the two types of nuclear reactions?

Answer 3

Fission and Fusion

Question 4

Why do p+ stay together in the nucleus? (3)

Answer 4

1. Strong nuclear force
2. Overcomes electromagnetic repulsion
3. Between protons

Question 5

Definition of Nuclear Reaction (3)

Answer 5

1. Unstable nuclei
2. Undergo spontaneous
3. Changes of number of protons and neutrons

Question 6

Definition of Nuclear Fission (3)

Answer 6

1. Nucleus splits into smaller nuclei
2. Releasing energy
3. Utilized in nuclear reactors for power

Question 7

What are the steps in a nuclear fission chain reaction? (8)

Answer 7

1. Neutron bombards radioactive nucleus
2. Initiates the nuclear reaction
3. Nucleus splits
4. Nuclei decays
5. Releasing energy and neutrons
6. Neutrons strike other nearby nuclei
7. Nuclei decays and release more neutrons
8. Creating a nuclear chain reaction

Question 8

What element has the most stable nuclei?

Answer 8

Iron (Fe)

Question 9

Does fusion or fission release more energy and create more stable isotopes?

Answer 9

Fusion

Question 10

Graph (READ)

Answer 10

Increase for Light Nuclei: Starting from hydrogen, the stability increases as the number of nucleons increases.

Peak at Iron: The highest binding energy per nucleon is found around iron (Fe), indicating maximum stability.

Decrease for Heavy Nuclei: Beyond iron, the binding energy per nucleon gradually decreases as the number of nucleons increases, making nuclei less stable.

This graph visually demonstrates why fusion stabilizes light nuclei and fission stabilizes heavy nuclei.

Question 11

Definition of the Fusion (3)

Answer 11

1. 2 smaller nuclei combine into a bigger nucleus
2. Nucleus is more stable
3. LOTS of energy is released as heat

Question 12

Definition of Half Life (2)

Answer 12

1. Amount of time for 1/2 of a sample to decay
2. NEVER AFFECTED BY A CHEMICAL OR PHYSICAL CHANGE

Question 13

Are elements more alike when it is in the same group or in the same period? (3)

Answer 13

1. Same Group
2. Same VE
3. VE account for 1/3 of Chemical Properties

Question 14

What is the formula for Natural Decay?

Answer 14

Big = Nearly Big & Decay Particle

Question 15

What is the formula for Artificial Transmutation?

Answer 15

Big + Neutron = Nearly Big + Decay Particle

Question 16

What is the formula for Fission?

Answer 16

Big + Neutron = 1/2 Big + 1/2 Big + Neutrons

Question 17

What is the formula for Fusion?

Answer 17

Small + Small = Big

Question 18

Why is Fe - 56 the most stable nucleus?

Answer 18

It has the highest binding energy per nucleon

Question 19

What is the difference between a nuclear reaction an raidoactive decay?

Answer 19

Radioactive Decay - Releases energy and a decay particle to achieve stability
Nuclear Reaction - Nuclei of atoms combine and react, leading to the production of energy and transformation of elements