1. Oxygen (O2) gases: medical use, welding 2. Nitrogen (N2): fire suppression, provides an inert atmosphere 3. Helium (He): balloons, medical equipment 4. Argon (Ar): welding, provides an inert atmosphere for materials 5. Carbon dioxide (CO2): carbonated soft drinks 6. Acetylene (C2H2): welding 7. Propane (C3H8): fuel for heat, gas grills