Where did you go today? Any chemistry involved?

Last week after I wrote that post I climbed into a helicopter at the PE airport and headed north east.
An internal combustion engine got me there - that combustion involved the reaction of fuel consisting mostly of carbon and hydrogen (hydrocarbon) with air which contains oxygen.
During the combustion the carbon in the fuel forms carbon dioxide. Possibly carbon monoxide will form as well, and hopefully no carbon(black smoke). The hydrogen combines with oxygen from the air to form water. Along with these gases - carbon dioxide and water vapour - comes a lot of heat. The hot gases are what drive the 4 cylinder engine in the small chopper I went up in.

Now being off the ground and a bit closer to the sun I thought of the ozone layer.

Ozone, (O₃)  is a form of oxygen that is unstable and readily reverts back to oxygen ( O₂) as we know it, and breathe it. It has a short half life - about 30  minutes. That means the concentration drops by 50% in 30 minutes. Higher up in the atmosphere (10 -50 km up) energetic radiation from the sun can break normal oxygen apart to form two free oxygen atoms that are reactive. These can then react with another normal oxygen atom to form ozone.

    O₂ + light = 2 O.  

     O  +  O₂  = O₃

This is how ozone forms in nature. The ozone layer protects us and other life forms from UV radiation by absorbing most of that harmful light. Click here for a link to how ozone is distributed in the atmosphere.

Lightning can also split apart oxygen allowing it to form ozone.
We can make ozone using sparks in a corona discharge tube. Air (or pure oxygen) is pumped through the tube and an air ozone mixture comes out.  A strong UV light will also make ozone.

Ozone is used mostly in water treatment for drinking, swimming pools, of aquaculture.  It kill bugs or oxidizes unwanted pollutants.

So that is a bit of natural chemistry (photo chemistry) that happens each day, and saves our bacon in the process. Look up, and imagine the ozone formation, or next time there is a fine electric storm - imagine the lightening forming ozone.


Now back to my flip in the chopper. About 12 km northeast of the airport I looked down at the Coega harbour.

Now there's is a big project that involved plenty of chemistry.
Obviously a lot of fuel was burned to build that wall.

Each of those dolosse (wave breaking structures) lying down there on the sides of the wall weighs about 30 tonnes. That's a lot of cement used to make the concrete!


Ah! yes, I have walls around me now, and you probably do too. Mostly these walls are made of brick and cement.

What is cement?

How is it made?

How does it get hard? Does it dry? My builder says yes, in fact he wants it to dry fast so he can paint and get on with the next job.

What does the chemistry suggest? Dry it fast?

In a subsequent post I will talk about cement manufacture and setting ; and perhaps we can have a closer look at the Coega wall - I will take you into the wall, and under the water...