Density and pressure test revision Flashcards
equation for density
density= mass / volume
equation for pressure
pressure= force / area
pressure at a point in a gas or liquid at rest acts…
… equally in all directions
equation for pressure difference
pressure difference= height x density x gravitational field strength
Why does heating a system change energy stored, increasing temperature or produces a change of state
Sometimes the heat turns to kinetic energy, which increases temp, others it is used to break the bonds, which leads to change of state.
change of state from solid to gas
sublimation
change of state from gas to solid
deposition
arrangement of particles in a solid
tightly packed, held in a fixed position. vibrate in fixed position
arrangement of particles in a liquid
forms shape of their container, still connected but can move around and slide over each other
arrangement of particles in a gas
very spread out, bounce around in quick and random motion
what is specific heat capacity
the energy required to change the temp of an object by one degree celsius per kilo of mass (J/Kg degrees C)
specific heat capacity equation (change in thermal energy equation)
change in thermal energy = mass x specific heat capacity x change in temp
why do gas molecules exert pressure on the walls of their container
Gas molecules have a rapid and random motion, so when they bounce off the walls of their container, they
exert a force. Pressure = force / ares, so there’s pressure as well.
Why is there an absolute zero of temp, and what is it
Absolute zero is the temp at which particles have no kinetic or thermal energy, so cannot exert a force
Absolute zero = 0 Kelvin = -273 degrees C
conversion between kelvin and celsius
celsius = kelvin - 273
kelvin = celsius + 273
