P2.5 What happens when radioactive substances decay, and the uses and dangers of their emissions Flashcards
1
Q
- If an atom of carbon has a mass number 14 and atomic number of 6 describe what this tells us about the number of electrons, neutrons and protons in the atoms.
A
- 6 protons, 8 neutrons, 6 electrons
2
Q
- What is meant by ionisation?
A
- Loss or gain of electrons
3
Q
- State what an alpha and a beta particle are made up of.
A
- alpha - helium nucleus/2p + 2n; beta - high speed electron
4
Q
- Which type of radiation is: most ionising? Most penetrating?
A
- alpha, gamma
5
Q
- What is produced during the fission of Uranium 235?
A
- 2 daughter nuclei and 2 or 3 neutrons and lots of energy released
6
Q
- Describe what is meant by a ‘controlled nuclear chain reaction’.
A
- When some of the neutrons released by the fission of Uranium 235 are absorbed by other materials, meaning that only one of the two neutrons released goes on to be absorbed by another Uranium 235 nucleus, limiting the amount of energy released.
7
Q
- Explain the difference between nuclear fission and nuclear fusion.
A
- Nuclear fission is the splitting of a large nucleus whereas fusion is the joining of small nuclei
8
Q
- Describe the process whereby the energy from a nuclear reactor core is converted into electrical energy in 5 steps.
A
- Heat energy transferred to a coolant which is usually water. This super-heated water is pumped to a heat exchanger where it is used to generate steam. The steam turns a turbine, which turns a generator which turns kinetic energy into electrical energy.
9
Q
- What problem is associated with the products of nuclear fission?
A
- They’re radioactive
10
Q
- Define Nuclear fusion
A
- the creation of large nuclei from smaller nuclei accompanied by the release of lots of energy
11
Q
- By what process do stars obtain their energy?
A
- Nuclear fusion
12
Q
- Why does nuclear fusion only happen at high temperatures and pressures?
A
- It is need to overcome the electrostatic repulsion of protons.
13
Q
- What are the 2 main dangers of ionising radiation?
A
- tissue damage, possible mutations in DNA
14
Q
- Thorium and radium used to be put in face creams back in the 1900’s. Why is this no longer done?
A
- Scientists became aware of the hazards and risks.
15
Q
- How can nuclear waste be disposed of and stored in the long term?
A
- Stored in concrete, steel and glass containers.