Thermal/Nuclear Energy

Question 1

Thermal energy

Answer 1

Total kinetic and potential energy of atoms in a substance - related to mass

Question 2

Heat

Answer 2

The transfer of thermal energy

Question 3

Temperature

Answer 3

Measure of average kinetic energy

Question 4

100 g of water at 50 degrees vs 500 g of water at 50 degrees. Comparison of temperature and thermal energy?

Answer 4

Temperature is the same, 500 g of water has more thermal energy due to greater mass

Question 5

3 methods of heat transfer

Answer 5

Conduction, convection, radiation

Question 6

Conduction

Answer 6

Requires physical contact. When fast moving particles of a warmer object collide with the slower particles of a colder object, thermal energy is transferred from the warmer object to the colder

Question 7

Convection

Answer 7

Transfer of thermal energy through a fluid. Colder, denser fluid falls and pushes warmer, less dense fluid up

Question 8

Radiation

Answer 8

Transfer of thermal energy as electromagnetic waves. Doesn’t not require any collision or movement of particles

Question 9

Thermal conductors

Answer 9

Allow thermal energy to pass through them easily and quickly

Question 10

Thermal insulators

Answer 10

Don’t allow thermal energy to pass through them easily and quickly

Question 11

Best thermal insulator and why?

Answer 11

Vacuum; little to no particles, so thermal energy can’t be transferred by conduction or convection. Mirrored surface in thermos reflects radiation

Question 12

Specific heat capacity

Answer 12

Amount of energy required to increase the temperature of 1 kg of matter by one degree

Question 13

Quantity of heat

Answer 13

Total amount of thermal energy transferred from a warmer substance to a colder substance. Directly proportional to mass, heat capacity, and change in temperature. Q = mct

Question 14

Principle of thermal energy exchange

Answer 14

Amount of energy lost by a warmer object is equal to the amount of energy gained by the colder object

Question 15

Thermal expansion

Answer 15

When a substance absorbs thermal energy, some of the energy becomes kinetic energy, and particles spread out, causing the substance to increase in volume

Question 16

Thermal contraction

Answer 16

Energy is lost, including kinetic energy, and particles don’t spread out as much, causing the substance to decrease in volume

Question 17

Latent heat

Answer 17

Thermal energy absorbed or released during a change of state

Question 18

Nucleons

Answer 18

Protons and neutrons

Question 19

Antiparticles

Answer 19

Same mass, opposite charge. Add a bar on top of the symbol.
Proton -> antiproton
Neutron -> antineutron
Electron -> positron

Question 20

Antimatter

Answer 20

Matter composed only of antiparticles

Question 21

Ionizing radiation

Answer 21

Waves/particles with enough energy to remove an electron from an atom, turning it into a positive ion. Ions created can cause cell damage

Question 22

Nuclear radiation

Answer 22

Ionizing radiation emitted from a nucleus. An unstable nucleus emits particles/EM radiation (radioactivity) in an effort to stabilize itself.

Question 23

Background radiation

Answer 23

Ionizing radiation. Human activity has contributed to natural background radiation

Question 24

Radioactive decay

Answer 24

Parent nucleus decays into daughter nucleus. Unstable atom tries to stabilize itself

Question 25

Alpha decay

Answer 25

Emits an alpha particle (helium nucleus). Greater chance in a larger nucleus than a smaller one. Strong interaction that holds nucleons together is stronger than the electromagnetic force, which pushes protons apart, but it has a shorter range

Question 26

Beta decay

Answer 26

Sometimes when a nucleus has too many neutrons to be stable it decays be emitting an electron. A neutron transforms into a proton. An electron and antineutrino are emitted.

Question 27

Neutrino

Answer 27

No charge, very little mass, rarely interact with matter

Question 28

Mass, speed, penetration, charge, and ionizing ability of alpha, beta, and gamma particles?

Answer 28

Alpha: heavier, slower, can't penetrate skin, +2 charge, high ionizing ability Beta: Lighter, faster, can penetrate 1 cm into body, -1 charge, moderate ionizing ability Gamma: no mass, speed of light, most penetrating, no charge, least ionizing ability

Question 29

Gamma decay

Answer 29

Sometimes after alpha/beta decay, nucleons are in an excited state - rearrange into a lower energy state by emitting EM radiation - gamma photon instead of photon because energy levels are greater.

Question 30

Isotopes

Answer 30

Same protons, different neutrons. Same chemical properties but different radioactive properties

Question 31

Radioisotopes

Answer 31

Unstable, spontaneously change their nuclear structure

Question 32

Fission

Answer 32

Nucleus splits into smaller pieces

Question 33

How does fission differ from radioactive decay?

Answer 33

Not spontaneous, triggered by neutrons, and it releases lots of energy

Question 34

Fusion

Answer 34

2 small nuclei fuse together, releasing more energy than fission. No dangerous waste products, but it can be hard to reach the required temperature

Question 35

Mass-energy equivalence

Answer 35

E = mc^2. Energy and mass are equivalent

Question 36

Law of conservation of mass-energy

Answer 36

Mass can transform into energy and vice versa, so long as the total is consistent

Question 37

Mass defect

Answer 37

During a nuclear reaction, a small amount of mass disappears. This difference is equivalent to the amount of energy released

Question 38

Why do we use half-life?

Answer 38

Nuclear decay reactions are spontaneous and there's no way to predict when a particular nucleus will disintegrate, but we can predict the decay rate for a large sample.

Question 39

Half-life

Answer 39

Average time it takes for a material to decay to half its original mass. (After 30 minutes it's halved, after another 30 it's halved again)

Question 40

Carbon dating

Answer 40

Ratio of C-14 to C-12 is equal in living things, but when something dies it no longer ingests carbon. As C-14 decays, the C-14 to C-12 ratio is reduced by half every 5730 years. Used to determine time of death