A well-established semiclassical method is used to systematically study the properties of hot dense matter in the conditions prevailing during the gravitational collapse of massive stars. Different semiclassical kinetic energy and entropy densities are discussed. Detailed results for different nuclear forces having different nucleon effective mass and nuclear incompressibility are presented. Plasma effects (translational and vibrational energies and Coulomb excess) are considered for a typical adiabat. The results presented here cover a wide range in entropy per baryon and electron concentration per baryon, for baryon densities ranging from 0.001/cu fm to 0.3/cu fm.