solids, liquids and gases Flashcards
what is meant by density of a material?
its the mass per unit volume of the material
example
- it states how many kg is the mass of one meter cube of the material
what is pressure?
the amount of force applied per unit area
how many newtons of force applied per meter square
in solids, pressure acts in the direction of force
which direction does pressure act in liquids and gases?
it acts equally in all directions
how do you convert between degree celsius and kelvin?
celsius to kelvin = + 273
kelvin to celsius = - 273
explain why kelvin scale is used in science instead of celsius scale
kelvin scale is directly proportional with the average kinetic energy (average speed) of the particle
at 0 kelvin the particles don’t move but at 0 c particles still move
what is absolute zero?
-273 C or 0 K
particles have no kinetic energy and do not move
explain the pressure of a gas in terms of the motion of particles
the particles move in random directions. when they collide with the walls of a container they exert a force which ascts at a right angle to the container
this causes pressure
how does changing the volume of a gas affect the pressure of the gas?
volume and pressure are inversely proportiona assuming themperature and mass of the gas is kept constant.
therefore as volume decreases (gas is compressed) pressure increases
as volume increases (gas in expanded) pressure decreases
how does changing the temperature of a gas affect the velocity of the particles?
the higher the temperature, the more kinetic energy the particles have and therefore the faster the average velocity of the particles
how does temperature affect the pressure of a gas?
increasing temperature increases the average kinetic energy of particles so they move faster
therefore particles collide harder and more frequently
this increases the pressure
does a gas have a high or low density and why?
a low density
because there is no attraction between the particles meaning that they are very spread out
this means there are less particles per unit volume
why is a liquid described to have a moderate density but still similar to that of a soild?
the particles are tightly packed together but can slide over each other
what is specific heat capacity?
the energy required to raise one kilogram of material by one degree celsius
how can unwanted energy be transferred while heating can be reduced?
through using insulation, which prevents energy being transferred to the surroundings
