3.2 Internal Energy and Energy Transfers Flashcards
what is the internal energy of a substance?
- the energy stored by the particles
- the sum of the total kinetic and potential energies that make up the system
what two things can heating a substance do?
- raise its temperature
- change the state of the substance
how does heating affect the energy of a substance?
- heating transfers energy to the substance
- it increases the energy of the particles that make up the substance
what three factors determine the temperature change of a system?
- mass of substance being heated
- type of material (specific heat capacity)
- energy inputted into the system
define specific heat capacity.
the amount of energy needed to increase the temperature of 1kg of a substance by 1°C.
state the equation used to calculate the temperature change when a substance is heated.
- ΔE = m c Δθ
- energy (J), mass (kg), specific heat capacity (J/kg/°C), temperature (°C)
describe how the internal energy and temperature of a substance changes when a change of state occurs.
- the internal energy of the substance will be increased or decreased
- the temperature of the substance will remain constant
define specific latent heat.
the amount of energy needed to change the state of 1kg of a substance with no change in temperature.
state the equation for the energy required to change state.
- energy to change state = mass x specific latent heat
- energy (J), mass (kg), specific latent heat (J/kg)
what is the specific latent heat of fusion?
the energy required to change 1kg of a substance from solid state to liquid state without a change in temperature.
what is the specific latent heat of vaporisation?
the energy required to change 1kg of a substance from liquid state to gas state (vapour) without a change in temperature.
