kinetic theory

Explain why the thermal motion of the helium atoms causes the broadening of the spectral lines.

there will be a change in frequency in the helium ions as they are moving

decreased wavelength for particles moving away from observer

increased for towards

Explain, using ideas of momentum, why the pressure exerted by a gas increases as the temperature of the gas increases.

as gas temp increases the kinetic energy increases

greater ke means momentim of atoms increase

greater frequency of collision of atoms with walls

rate of change in momentum is equal to force

p=f/a and force on walls is greater

temperature is constant because average ke of the molecules in the puree is constant

when boiling occurs the thermal energy supplied increases the potential energy of molecules causing them to move further apart

how atoms emit light

electrons transition between energy levels in atoms

when electrons return to a lower level they emit energy in the form of photons