Doc, what is the difference between pneumothorax and emphysema? thank you.i am a med student

Big difference: pneumothorax when the integrity of negative pressure around the lung were violated, so air escape from outside in and push against the lung to the point of collapse,tension pneumothorax when the lung completely collapsed. emphysema is a chronic disease, where the alveoli get so stretched it loose the alasticity and air get trapped inside, and that will cause problem with exchange of the O2 and CO2