thermal physics Flashcards
what is internal energy
the sum of kinetic and potential energies of all particles in a gas
where do the kinetic energy and potential energy in a gas come from
kinetic- the random movement of particles
potential- the interaction between particles
what happens when heated is added to a system
the system increases in energy but not always in temperature
what is the specific heat capacity
the energy needed to raise 1kg of a material 1k
what is the specific latent heat
the energy required to change an objects state
what happens to the energy put into a system to change its state
the energy is used to weaken the intermolecular bonds. The energy doesn’t increase kinetic energy so the temperature doesn’t increase
what are the types of specific latent heat
latent heat of fusion- melting point
latent heat of vaporisation- boiling point
absolute zero (°C)
-273 °C
what does Avogadro’s number describe
the number of molecules in 1 mole of any substance
what is the atomic mass unit
the mass of one proton or neutron
what is Boyle’s law
pressure and volume of a pass are inversely proportional at a constant temperature and mass
practical for Boyle’s law
- connect a gas syringe to a pressure sensor
- connect the sensor to a data logger and computer
- move the plunger in small steps so the temp doesn’t change
- record pressure at each volume
- plot a volume^-1 - pressure graph
- draw a line of best fit (should go through 0)
this proves they are inversely proportional
what is Charles’ law
volume and temperature(in kelvin) are directly proportional for a gas at constant mass and pressure
what was the first direct evidence for atoms
Brownian motion. the random motion of tiny particles caused by the random collisions of atoms with the particles in a fluid
what did Robert Brown notice
tiny pollen grains randomly changed direction when suspended in still water without colliding with other pollen grains
