Paper 1 Flashcards
kelvin to degrees
k = c + 273.16
thermal equilibrium
if two substances are in contact and one is hotter than the other there will be a new flow of thermal energy from the hotter object to the cooler object till they reach thermal equilibrium
properties of solids
*strong electrostatic forces of attractions
* kinetic energy and they vibrate around their fixed positions
properties of liquid
greater mean seperation
more kinetic energy still electrostatic attraction
properties of gaseous phase
most kinetic energy
travel with random speed and direction
brownian motion
molecules of a gas travel in random directions with random velocity, can be observed in smoke particles under a microscope, random movement because of collisions with other particles which transfers momentum
internal energy
sum of the randomly distributed kinetic and potential energies associated with the atoms or molecules which make up the substance
when a substance is heated but remains in the same state
kinetic energy of the molecules increases but the potential energy remains the same
when a substance changes state
potential energy increases but the kinetic energy remains the same. temperature of the substance stays the same because the thermal energy is being used to overcome electrostatic bonds between molecules.
absolute zero
this is at 0 kelvin and when all the molecules in a substance stop moving completely.
specific heat capacity
energy required per unit mass to increase the temperature by 1k.
given by the equation E = mc∆𝜃
how can we know the specific heat capacity of a substance using an electrical heater
- known mass of a substance is heated by an electrical heater with known power for a given time
- initial and final temperatures of the substance are measured.
- energy transfer is equal to power multiplied by time, VI = mc∆𝜃/t and rearrange to find c.
- an insulator is used around the substance to minions external energy transfer.
Specific latent heat
energy required per unit mass to change the phase of a substance from solid to liquid
Specific latent heat of vaporisation
energy required per unit mass to change the phase of a substance from liquid to gas, the formula being E = mL
determine specific latent heat of a substance
use similar setup when an object is chasing phase the temperature is constant is used as the time when calculating the energy transferred to the substance
how many particles in a mole
6.02x10^23 this can be determined by multiplying the number of moles of a substance by avagadros constant. the number of moleskin, of a substance is determined as
m = mass, M = molar mass
n = m/M
how do particles in an ideal gas behave
- gas contains large number of atoms with brownian motion
- volume is negligible when compared to the total volume of the gas
- all collisions are perfectly elastic
*time taken for atoms to collide is negligible compared to the time between collisions - electrostatic forces between atoms are negligble except when colliding
Boyles law
for a fixed mass of gas at a constant temperature the pressure is inversely proportional to the volume
Charles law
for a fixed mass of gas at a constant volume, the pressure is proportional to temperature.
what 2 laws are compiled to produce the pressure volume equation
pV =nRT
Charles law and Boyles law
p = pressure, V = volume, n = no. of. moles, R = molar constant, T temperature
investigating Boyles law
pressure exerted is inversely proportional to its volume,
sealed syringe filled with gas connected to a pressure gauge. string can be used to vary the volume of the container and values of volume and pressure are recording.
root mean square speed
pressure exerted by a gas and the mean kinetic energy of molecules in the gas are related to the root mean square speed of the molecules.
pV = 1/3 Nmc^2
the Maxwell Boltzmann distribution
shows the number of molecules with each speed against speed c, area under the graph represents total number of molucules. as temperature increases the peak of the graph shifts to a higher speed
Boltzmann constant
pV = nKT
internal energy of an ideal gas
sum of the kinetic and potential energies, the kinetic energy is equal to the total internal energy as there are no electrostatic forces between the molecules
angular velocity
rate of change of angle it is given by the formula w = ∆𝜃/t = 2(pi)(f)
centripetal force
net force which acts perpendicular to the direction of the velocityy towards the centre of the circle.
F = mv^2 /r
v = 2πr/t = wr
simple harmonic motion
type of oscillation where the acceleration of the oscillator is directly proportional to the displacement from the equilibrium position and acts towards the equilibrium position.
a = -w^2x
analysing simple harmonic motion, equations for the displacement of an oscillator
x = Asin(wt)
x = Acos(wt)
velocity and acceleration of oscillations
maximum velocity occurs at equilbrium position with the oscillator being stationary at the amplitude points. maximums accerlation occurs at the amplitude points and is 0 when the oscillator is at equilibrium
v = +-W sqrt(A^2 - X^2)
damping
the process by which the amplitude of the oscillations decreases over time this is due to energy loss to resistive forces such as drag and friction
types of damping
light - occurs naturally and the amplitude decreases exponentially
heavy - amplitude decreases dramatically
critical - object stops before one oscillation is completed
free oscillation
no external forces are being applied it oscillates at its natural frequency