Topic 7 - Solids, Liquids & Gases Flashcards
Density equation
density = mass/volume
ρ = m/v
(kg/m^3 OR g/cm^3)
Pressure equation
pressure = force/area
P = F/A
1Pa = 1N/m^2
Pressure difference equation
pressure difference = height × density × gravitational field strength
P (Pa) = h × ρ × g (N/kg)
Specific heat capacity
This is the amount of energy needed to raise
the temperature of 1kg of a material by 1°C
Thermal energy equation
change in thermal energy = mass × specific heat capacity × change in temperature
ΔQ = m × c × ΔT
Q = Joules
c = J/kg °C
Absolute zero
At absolute zero the particles have no thermal energy or kinetic energy, so they cannot exert a force. Therefore, there is no motion.
Celsius -> Kelvin
+ 273
Kelvin -> Celsius
- 273
Kelvin
Unit of temperature, symbol K. The Kelvin temperature of the gas is directly proportional to the average kinetic energy of its molecules
Qualitative relationship between pressure and volume at constant temperature
Pressure ↑ Volume ↓
Pressure ↓ Volume ↑
Qualitative relationship between pressure and Kelvin temperature at constant volume
Pressure ↑ Temperature ↑
Pressure ↓ Temperature ↓
Boyle’s Law
P∝1/V
P1V1 = P2V2
Gay-Lussac Law
P∝T
P1/T1 = P2/T2
*Temperature needs to be in Kelvin
Pressure
the continuous force of something in contact with something else (e.g. atmospheric pressure)
1 ATM
100,000Pa
Physical change
Doesn’t change what the substance is in terms of composition, but changes the state, shape or size of the object. They are often reeversible.
Chemical change
Two or more substances becoming chemically bonded together to produce a new substance. Most chemical changes are difficult to reverse.
Temperature
A measure of particles in motion - the average kinetic energy of the molecules
Properties of solids
- Can’t flow
- Fixed shape
- Fixed volume
- Higher density than a gas and liquid
Properties of liquids
- Can flow
- No fixed shape (fits shape of container)
- Fixed volume
- Higher density than a gas
- Lower density than a solid
Properties of gases
- Can flow
- No fixed shape (fits shape of container)
- No fixed volume
- Lower density than solids or liquid
Change of state
A physical change that occurs when a substance transitions from one state of matter to another
Heat is added or taken away.
Heat energy:
1. Changes KE of particles
2. Changes potential (stored) energy of the substance
When a substance is changing state, temperature stays constant
Brownian motion
the random movement displayed by small particles in a gas or liquid
Experiment: Robert Brown observed pollen on water
Explanation: when water particles and pollen collide, we only observe the effects of the collisions because water particles are too small to see
Air pressure
caused by collisions between air particles and their surrounding surfaces
