Thermal Physics

Question 1

States of Matter

Answer 1

Solid Liquid Gas Plasma

Question 2

States of Matter Particle Arrangement

Answer 2

Solid: Always touching and are locked in place, vibrate.
Liquid: Always touching but are not locked in place and have a bit of space to move.
Gas: Not touching, vast space between them, always moving.

Question 3

Brownian Motion

Answer 3

Brownian motion is evidence of the kinetic particle model. It shows that when small particles when viewed under a microscope, such as pollen grain in water or smoke, can be seen having random motion. This is the microscopic particles are being hit by smaller particles in the liquid or gas, hitting the pollen grain and making it move.

Question 4

Pressure and temperature at constant volume.

Answer 4

When the volume of gas stays constant in a chamber, if the temperature increases then so will the pressure. This is because when the temperature increases the kinetic energy of the particles increases and so they collide with the walls of the container with more force, therefore exerting more pressure.

Question 5

Pressure and Volume at constant Temperature.

Answer 5

When a piston pushes the air in an enclosed space, the volume will decrease and the pressure will increase, which is due to the particles being in a smaller space and so they are colliding with the walls more frequently which increases pressure. If the volume of the container is halved, then the pressure on the piston will be doubled and the collisions per second will also be doubled.

Question 6

Kelvin

Answer 6

K = 0 = -273C
K = 5
K = 275
K = 300
C = 0
C = -100
C = 45

Question 7

Specific Heat Capacity

Answer 7

Change in Energy = Specific Heat Capacity x Mass x Change in Temperature
∆E = cm∆T

Question 8

Difference Between Boiling and Evaporation

Answer 8

Boiling:
Happens at a specific heat.
Is throughout the body of the liquid.
Surrounding temperature increases

Evaporation:
Happens only on the surface of the liquid
Any temperature
Surrounding temperature decreases

Question 9

Evaporation

Answer 9

Evaporation is when the particles with a higher energy leave the surface of the liquid to form vapour, decreasing the average energy of the liquid.

Question 10

Conduction

Answer 10

When heat is transferred through something. Solids are good conductors because their particles are touching, liquids are weak conductors because they have weak chemical bonds, gases are very poor conductors because they are so far apart.

Metals are very good thermal conductors. This is because they are solids, but also because they have delocalised electrons. Which means that they can also conduct heat around the solid.

Question 11

Convection

Answer 11

Convection can only happen in fluids (liquids and gas). Heat causes the particles to move faster and further apart making them less dense. These means that the hot particles or less dense ones will rise in a fluid, past the cold ones, and the more dense ones fall to the bottom. This creates a convention current and is how thermal energy is transferred.

Question 12

Radiation

Answer 12

Radiation does not require particles, to transfer Thermal Energy. Radiation can be carried through vacuum, like the heat of the sun being carried through space. It is mostly infrared radiation.
Radiation being edited or absorbed or reflected will depend on the colour and texture of a surface.
If a surface is black and dull then it will absorb a lot of radiation and also emit a lot.
A shiny white surface will reflect a lot of radiation meaning it will not absorb a lot of it, and will not emit much either.

rate of emission is greater with a larger surface temperature of the object and a larger surface area.