energy Flashcards
what is a system?
a system is an object or group of objects
what happens when a system changes?
when a system changes there are changes in the way energy is stored
what is internal energy?
internal energy is the total kinetic and potential energy of all the particles that make up a system
what does heating the system do?
heating increases the energy of the particles within it.
what can happen if there is an increase in energy?
- increase the temperature
- produce a change of state
the temperature increase depends on:
- mass of substance heated
- what the substance is
- the energy input
what is the specific heat capacity of a substance?
The specific heat capacity of a substance is the amount of energy required to raise the temperature of 1 kg of the substance by 1°C
two keys points about energy transfers
- Energy can be transferred usefully stored or dissipated (spread out to the surroundings)
- energy cannot be created or destroyed
what happens in a closed system?
in a closed system the total energy never changes, but it can be transferred from one store to another
how is wasted energy caused?
wasted energy is caused by unwanted energy transfers
how can you reduce unwanted energy transfers?
-lubrication (reduces friction that produces heat) -Tightening loose parts (prevents unwanted vibration) -thermal insulation (reduces heat loss)
what are the main uses of energy?
transport, electricity, generation and heating
renewable:
can be replenished
non-renewable:
eventually run out
non renewable resources
- nuclear fuel
- coal
- gas
- oil
