A2 Physics Thermodynamics

what is internal energy

the sum of kinetic energy and potential energy of random motion of molecules in a system

what does a change in temperature do to internal energy

an increase in temperature increases the kinetic energy of a system and therefore increases the internal energy

formula for work done on the gas

W = p Δ V

sign differences in work done on gas

work done on gas: compressed (+W)

work done by gas: expands (-W)

formula for first law of thermodynamics

ΔU = q + W ; ΔU is change in internal energy, q is heating of the system, and W is work done on the gas