By abundance in the atmosphere:
* Nitrogen (N2): Makes up about 78% of the Earth's atmosphere, making it the most abundant gas.
* Oxygen (O2): Second most abundant, at about 21%. It's essential for life on Earth.
By everyday use:
* Nitrogen (N2): Used in food packaging, tire inflation, and even to create the atmosphere for semiconductor manufacturing.
* Oxygen (O2): Used in hospitals, welding, and for breathing apparatus.
* Carbon Dioxide (CO2): Used in carbonated drinks, fire extinguishers, and as a plant food in greenhouses.
* Helium (He): Used in balloons, party decorations, and in scientific instruments.
By chemical properties:
* Noble gases (He, Ne, Ar, Kr, Xe, Rn): They are very unreactive and often used in lighting, lasers, and medical imaging.
So, which gas is "common" depends on what you're looking for! Let me know if you have a specific area in mind, and I can help you identify the most common gas in that context.
