Opacity is a function of the temperature and electron density of plasma. The plasma density can be determined by measurements of Stark-broadened K-shell spectral lines. The purpose of this work is to obtain a more detailed structure of opacity with regard to broadening effects. For this aim, the opacity frequency dependency and mean opacity of mixed plasmas are calculated under local thermodynamic equilibrium (LTE) conditions. The LTE state in inertial confinement fusion occurs when the collisional deexcitation rate from the upper level to the lower level greatly exceeds the spontaneous decay rate. Since the thermal radiation can be absorbed by the CH-ablator, by studying the behavior of the CH Polystyrene opacity, one can obtain the temperature and density of the plasma in investigations of matter found in stellar interiors, inertial fusion implosions, and Z pinches as a diagnostic technique. The main aspect of diagnostic application is spectrum broadening. The final results show that the Stark-broadened line shape is dependent on the density. Also, it is shown that the resonance peak and spectrum broadening of the opacity spectrum of a mixed plasma such as the CH-plasma is larger than a single atom plasma such as Carbon. Published by AIP Publishing.