Why is the forward biased voltage for a typical red LED so much greater than the forward biased voltage for a typical silicon diode?

This is because as we know the magnitude of a forward voltage drop depends on the material used for constructing the diode and also the magnitude of the band gap, so since LED material are generally gallium arsenide and gallium phosphide which has the higher band gap than silicon and since the higher the band gap the higher the voltage drop so LED has the greater forward voltage drop then the silicon diode

graph slopes whilst gas cools, then it is flat whilst conensation to liquid happens, the coolong liquid then graphs as a slope when it solidifies graph is flat

latent heat