Section 9 - Gravitational and Electric Fields Flashcards
Internal energy depends on ____________
Kinetic and potential energy of particles
How is kinetic energy of particles distributed
Randomly
Internal energy def
The internal energy of a body is the sum of the randomly distributed kinetic energies of all its particles
System def
A group of bodies considered as a whole
Closed system def
A system which does not allow any transfer of matter inside or out
Internal energy for a closed system
For a closed system, the total internal energy is constant as long as not work is done by or done on the system
How can the internal energy of a system be increased
By heating or doing work on the system
What happens when a substance changes state [2]
- A change of internal energy takes place
- The temperature remains the same
Specific Heat Capacity (SHC) def
The specific heat capacity of a substance is the amount of energy needed to raise the temperature of 1kg of the substance by 1K (or 1C)
SHC formula
Energy change = mass * SHC * Change in temp
Q = mc(^T)
UNits of SHC
J/KgC or J/KgK
Finding the SHC using a continuous flow calorimeter SETUP
Finding the SHC using a continuous flow calorimeter STEPS
Specific latent heat (SLH) def
The specific latent heat of fusion or vaporisation is the quantity of thermal energy required to change the state of 1kg of a substance
SLH formula
Energy change = mass * SLH
Q = m*SLH
K to C conversion
K = C + 273
Kelvin def
0K is the lowest temperature possible, a system has no kinetic energy
Boyles Law in words
At a constant temperature the pressure and volume of a gas are inversely proportional
Boyles law formula
pV = k
Charles law in words
At a constant pressure, the volume of a gas is directly proportional to its absolute temperature
Charles law formula
V/T = k
The pressure law in words
At a constant volume, the pressure of a gas is directly proportional to its absolute temperature
Pressure law formula
p/T = k
Boyles law explaination
If you reduce the volume of a gas, its particles are closer together and will collide with each other and the container more often, so more force is exerted over the same area and the pressure increases
Charles law explaination
When you heat a gas, the particles gain kinetic energy. At a constant pressure, this means they more quickly and further apart, so the volume of the gas increases
The pressure law explanation
If you heat a gas, the particles gain kinetic energy. This means they move faster. If the volume doesn’t change, the particles will collide with each other and their container more often and at higher speed, increasing the pressure inside the container
Experiment to investigate Boyles law
Experiment to investigate Charles’s law
Molecular mass def
Molecular mass is the sum of the masses of all the atoms that make up a molecule
Avogadros constant definition
The number of atoms or molecules in one mole of a substance
Avogadros constant value
6.02 * 10^23
Molar mass def
The mass that 1 mol of a substance would have
Ideal gas equation
pV = nRT
n = number of moles
R = molar gas constant
Molar gas constant value and units
8.31jmol/K
The equation of state
pV = NkT
N = number of particles
k = Boltzmann’s constant
Boltzmann’s constant
1.38*10^-23 J/K
Pressure, volume, work done
Word done = p* change in V
Deriving pressure on one wall of a box
Ideal gas def
A gas that obeys the 5 ideal gas laws
Ideal gas laws [5]
