Solids, liquids and gases Flashcards
Density equation
(Kg/m3) = mass (kg) / volume (m3)
ρ = m/v
1000Kg/m3 =
1g/cm3 = density of water
The density of a stone
can be calculated by (dividing the mass of the rock) / (the volume of water being displaced)
volume of water displaced = volume of stone
Pressure equation
(Pa) = force (N) / area (m2)
P = F / a
Pressure in liquids and gases
The pressure increases with depth
Pressure in windows
Windows don’t collapse because the force applied inside is equivalent to the one aplied outside. So the resultant force is 0
Pressure at depth equation
(Pa) = height (m) * density (Kg/m3) * g(10)
P = hρg
Earth’s pressure at sea level
Pressure of earth’s atmoshpere at sea-level is 100 000 Pa
Pressure increase in earth
Under water, pressure increases 1 atmosphere (101325Pa) for every ten metres of depth
Barometer
When air pressure increases, the force acting on mercury increases, so it rises (sunny day). When air pressure decreases, the force acting on mercury decreases. Then mercury will go down (rain).
Absolute Zero
The temperature which particles have zero kinetic energy and do not move (there is a lowest posible KE)
0 K = -273ºC
Converting units (Kelvin to ºC)
Kelvin - 273 = ºC
Converting units (ºC to K)
ºC + 273 = K
Relationship (average KE vs Temp)
Average KE of particles is proportional to the temperature IN KELVIN
Relationship (average speed vs. Temp)
As average speed incresases, temp (kelvin) increases.
Explain why gases exert pressure on inside walls of containers
gas particles move at random
particles collide with
the WALLS of the container
Force exerted on walls because
pressure = force / area
Explain why the pressure increases by decreasing the volume
Decreases area of the walls of the container
Increase frequency of the collisions
with walls
Increase force
pressure = force / area
Explain why the pressure increases by increasing the temperature
Increase Kinetic Energy of particles
Increase frequency of the collisions
with the walls
Increase force of the walls because
Pressure = force / area
Pressure Volume equation
p1V1 = p2V2
Assumptions
fixed amount of gas (mass)
fixed temperature
p1V1 = p2V2
p1 = initial pressure I
p2 = final pressure I Units are the same
V1 = initial volume
V2 = final volume
Pressure Temperature equation
P1/ T1 = P2/ T2
P1/ T1 = P2/ T2
p1 = initial pressure I
p2 = final pressure I Units are the same
T1 = initial temperature I
T2 = final temperature I IN KELVIN
Assumptions
fixed mass of gas
fixed volume of gas
