Internal energy and energy transfers Flashcards
What is the internal energy of a substance?
The energy stored by the particles of a substance. this is the energy of the particles that is caused by their individual motion and positions
What is the internal energy of the particles the sum of?
- the kinetic energy they have to due to their individual motions relative to each other
- the potential energy they have due to their individual positions relative to each other
formula for internal energy of a substance
kinetic energy of particles + potential energy of particles
What happens when you heat a substance
- internal energy goes up
- observed by change of state
- or temperature increasing
What happens when you cool a substance
- internal energy goes down
- temeperature decrease
- change of state
How to calculate energy transferred using specific heat capacity
△E = m x c x △θ
energy = mass x specific heat capacity x temperature change
What is the definition of specific heat capacity?
the amount of energy needed to raise the temperature of 1kg of that substnace by 1°C
What happens to the temperature when a substance is changing state?
it stays constant as all of the energy is used to break the bonds between the particles
what is specific latent heat?
- amount of energy required to change the state of one kg of a substance with no change in temperature
How do you calculate specific latent heat?
E = m x L
energy = mass x specific latent heat
What do you call the specific latent heat of a substance changing state between a solid and a liquid?
fusion
What do you call the specific latent heat of a substance changing state between a liquid and gas?
vaporisation
How do you calculate energy transferred?
E = P x T
time is measured in seconds
