Solids, Liquids and Gases - GCSE Flashcards
what is density?
how much mass is packed into a given volume of space
density is the measure of what?
compactness of a substance
how do you calculate density?
density (p) = mass (m)/ volume (v)
what are the units of density?
g/ cm3 or kg/ m3. 1g/cm3 = 1000 kg/m3
what does the density of an object depend on?
what it is made of
density doesn’t vary with what?
size or shape
what does the average density of an object determine?
whether an object floats or sinks
a solid object will float on a fluid depending on what?
if it has a lower density than the fluid
how do you measure the volume of an object? (with regular shape, e.g a box shape)
measure its length, width and height with a ruler. Then calculate its volume by multiplying the length width and height together
how do you measure the volume of an object? (with irregular shape, e.g a rock)
put the rock in a eureka can filled with water. The water displaced by the object will be transferred to the measuring cylinder. Record the volume of water in the measuring cylinder. This is the volume of the object
what is pressure?
a measure of the force being applied to the surface of something
what is the formula of pressure?
pressure = force/ area
the same force applied over a large area creates what?
a lower pressure
in what direction does pressure act in gases and liquids at rest?
equally in all directions
what makes pressure increase in gases and liquids?
depth (e.g pressure is higher at the bottom of the sea than at the surface)
what is pressure difference?
the difference in pressure between two points in a liquid or a gas
what does pressure difference depend on?
- height difference (in m)
- density (in kg/ m3)
- gravity
what is the formula of pressure difference?
pressure difference = height x density x gravitational field strength
what makes solids become liquids?
melting
what makes liquid become gas?
boiling
what makes gas become liquid?
condense
what makes liquid become solid?
solidifies
what is the number for gravitational strength?
10 n/kg (newtons per kilograms)
what happens to particles when temperature is increased?
the particles have more energy (they move more quickly and vibrate more)
what happens to particles when temperature is decreased?
there is a reduce on the energy of particles
what is the coldest that anything can ever get?
-273 celsius
what is -273 celsius also known as
absolute zero
how are particles at absolute zero?
they have as little energy in their kinetic stores as it’s possible to get
what is -273 celsius the start of?
it is the start of the Kelvin scale
how do you convert degrees celsius to kelvins?
add 273
how do you convert kelvins to degrees celsius?
subtract 273
how do particles in gas move?
they move constantly and in a random direction
how much space does gas take?
nothing, most of gas is empty space
the temperature of gas in kelvins is proportional to what?
the average energy in the kinetic energy stores of its particles
anything that is moving has energy in what?
in its kinetic energy store
what is the energy in kinetic energy store equal to?
1/2 mv2
what do colliding gas particles create?
they create pressure
what do gas particles create in a sealed container when they smash against the container’s walls?
they create an outward pressure
what does the pressure depend on when gas particles smash against the container’s walls?
on how fast and how often they hit the walls
what makes particles move faster?
the increase of temperature
what happens if you double the temperature of a fixed amount of gas? (what happens to the pressure)
you double the pressure
what is the relation between temperature (in K) and pressure?
they are proportional
what happens if you reduce volume of a container with gas?
the particles get less space meaning more collisions are formed
what is the formula for constant?
pressure x volume = constant
you can also write the equation as:
P1 x V1 = P2 x V2 (P1 and V1 -> starting conditions, P2 x V2 -> ending conditions)
