Topic B physics

heat

the amount of energy transferred from a warmer object to a cooler object and measured in Joules

internal energy of an object

the sum of all kinetic energy of its molecules plus the intermolecular potential energy and measured in joules

a change in kinetic energy will change the .. of the system

temperature

a change in potential energy will change the … of the system

phase

Avogadro constant

amount of particles In one mole

mole

6,02 × 10²³ particles of something it is the SI unit for measuring the amount of a substance

molar mass

the mass of one mole of a substance

phases:

gas, liquid solid

the phase gas

molecules far apart and intermolecular and intermolecular forces are low (negligible for ideal gasses)

the phase liquid

molecules are closer together and intermolecular forces are bigger

the phase solid

molecules are packed together sometimes in a crystal and intermolecular forces are large

intermolecular bonds

are bonds that hold molecules together, according to molecular theory, a phase transition means the bonds get stronger or weaker

specific heat capacity

the energy needed to warm up 1 Kg of matter by 1 degree

specific latent heat

energy needed for 1 kg of matter to go through a phase change, during this process the temperature is constant

ideal gasses assumptions (Nites)

1. netwond law of mechanics apply

2. intermolecular forces are negligible

3. time of collisions are negligible

4. elastic collisions (no energy lost)

5. small point particles

pressure of gas macroscopic

is equal to the force applied per area and measured in pascals

pressure of gas microscopic

pressure indicates how often molecules are bumping into the sides of a container

pressure-volume law (Boyle’s law)

when temperature is constant pV=constant

volume-temperature law (Charle’s law)

when pressure is constant V/T=constant

pressure-temperature law (Guy-lussac’s)

when volume is held constant p/T=contant

are kinetic energy and temperature proportional in a gas?

yes

emissivity (conceptual definition)

a measure of a material’s ability to emit thermal radiation

emissivity (definition)

the ratio of the power radiated per unit area by a material to that of a black body of the same temperature

a black body

an ideal entity that absorbs all incident electromagnetic radiation and remits perfectly

albedo

the fractions solar energy reflected off a surface back into space (total scattered power/totral incident power)

Latitude

How far north or south of the equator a place is, with 0 degrees being the equator and 90 degrees being the north or South Pole.

green house gasses 4

1. methane (CH4)

2. water vapour (H20)

3. carbon dioxide (CO2)

4. nitros oxide (N20)

greenhouse effect

the mechanism where some of the incoming radiation of the sun is trapped within the earth surface-atmosphere system

greenhouse gasses

gases in the atmosphere that absorb infrared radiation directly from the sun and from the surface of the earth

conduction

transfer of heat through direct contact between particles

convection

transfer of heat through fluids by the collection of fast moving molecules from one place to another

radiation

the mechanism where thermal energy can pass directly between two bodies without increasing the temperature of the material in-between

luminosity

the amount of energy a black body emits

intensity

the power transferred per unit area

wien’s law

the wavelength at which the maximum intensity of radiation is emitted is related to the absolute temperature of a black body