By Scott Weatherwax
I had a phone call last week and a customer was looking for a product from e2v to monitor air quality. e2v manufactures gas sensing devices. I asked a few more questions, but then the customer asked me if I knew the chemical formula for air. This question caused me to pause, as I was not sure what was being asked. I explained that air is made up of a number of different substances:
Nitrogen (N2) = 78.08%
Oxygen (O2) = 20.95%
Argon (Ar) = 0.93$
Carbon Dioxide (CO2) = 0.033Trace elements of many other which total 0.007%.
The customer went on to explain that he was really a mechanical engineer and basically sat through chemistry. We both had a good laugh, but after the call I realized that due to circumstances beyond their control many engineers are being forced into roles in which they may not have complete academic domain expertise. This post will give a few of the most common chemicals and their chemical formulas which I hope will be helpful.
The most common questions asked are about formulas for the most commonly monitored Hydrocarbons.
The five most common hydrocarbons are:
- Methane = CH4
- Propane = C3H8
- Acetylene = C2H2
- Benzene = C6H6
- Ethylene = C2H4
Other gases and formulas are:
Ammonia = NH3 Carbon Monoxide = CO Carbon Dioxide = CO2 Chlorine = Cl2 Hydrogen = H2 Oxygen = O2 Ozone = O3 Hydrogen Sulfide = H2S Sulfur Dioxide = SO2 Butane – ISO = CH3 Nitrogen = N2 Nitrogen Dioxide =NO2 Nitric Oxide = NO Phosphine = PH3 Ethylene Oxide = C2H4O
Also, note that some gases have no formula per se. Air has no formula, as shown above. Another example is natural gas. Natural gas is made up of many elements and will often contain additives put in by municipalities. In fact, if you ask what is added to their natural gas, most municipalities will not tell you what is added, but just tell you it is proprietary information.
Also, VOC gases – Volatile Organic Compounds – are just that, organic compounds. Sensors that measure these gases have a pretty broad bandwidth, a very wide sensitivity range, and will respond to many organic compounds. You should always ask the vendor the sensitivity of the gas you need to monitor, as the sensitivity might be pretty small.
Hopefully these handy chemical gas formula references will help you with your gas sensing projects.
Comments