I had a phone call last week and a customer was looking for a product from e2v to monitor air quality. I asked a few more questions, but then the customer asked me if I knew the chemical equation for air. This question caused me to pause, as I was not sure what was being asked. I explained that air is made up on a number of different substances:
Nitrogen (N2) = 78.08%
Oxygen (O2) = 20.95%
Argon (Ar) = 0.93$
Carbon Dioxide (CO2) = 0.033
Trace 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 was completed I realized that due to circumstances beyond their control many engineers are being forced into roles which they may not have realized were going to happen. This blog will give a few of the most common chemical equation and the actual chemical that some may find helpful.
The most common question asked is the 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. Like what was shown above, air has no formula. Another example is natural gas. Natural gas is made up of many elements and in addition, most municipalities put additives into their natural gas. 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 proprietary information.
Also, VOC gases – Volatile Organic Compounds – are just that, organic compounds. These types of sensors have a pretty broad bandwidth and have 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.