When most people think of chemistry, I presume at least, I’d imagine science fair volcanoes or people in lab coats creating medicine or whatever. That being said, I doubt the average person knows just how much chemistry happening all around us. For example, driving to the gas station and picking regular gasoline instead of diesel is not chemistry in it of itself, but the reason for the choice boils down to chemical proportions in the fuel. A simple material like crude oil can form a multitude of different products with varying effects based solely on its composition, which I found interesting enough to write about.
See, gasoline and diesel have a similar chemical formula; both of them are hydrocarbons or “hydrocarbures” in French. The main difference between them is the number of atoms of Carbon and Hydrogen found in a molecule. As far as I understand, the oil used to make the two is the same, so they use titration to separate based on their chemical proportions in nature, then they will be refined into the state we know them as.
Knowing how atomic and molecular mass works, the molecules with more atoms are going to be heavier. Therefore, diesel, whose chemical formula is C12H23, will be much thicker and heavier than regular gas, whose formula is C8H18. This makes diesel harder than gas to breakdown and evaporate (which is how the titration works in the first place). In more practical terms, the chemical proportion of the hydrocarbon determines how efficient the fuel will be, as thicker fuels burn slower and last longer in turn. I also can assume diesel is used in trucks and larger vehicles as they are safer and less flammable (which is good for the cargo), again going back to the bonds in the molecule. For regular gasoline, it’s less viscous and more flammable, yet it is used in most cars for other reasons, like cost and resources.
If you thought those are the only variations of the molecule, you haven’t seen anything yet. More dense molecules with more carbon and hydrogen atoms form thicker, more solid products like petroleum jelly, or what’s commonly referred to as Vaseline. Even further, asphalt for roads is created using molecules with an even higher molecular mass. Granted, both of their chemical formulas do contain other participants (C15H15N for Vaseline and some sulfur in asphalt), they can only be made with corresponding hydrocarbons. On the other side of the spectrum, C3H8, or propane, as the name suggests, is a gas usually used to start fires for barbeques and the like. If it wasn’t clear why so many countries are desperate for oil, well, I’m pretty sure this answered the question for you….
Again, I’m not sure if this was what was meant for the prompt, but regardless, I find it extremely interesting that so many uses for the same crude oil simple depending on the quantity of carbon and hydrogen in the molecule. I wonder if there are more materials that act like crude oil, with its uses changing depending on its composition.
What’s the difference between gasoline, kerosene, diesel, etc? (2021, March 30). Howstuffworks. https://auto.howstuffworks.com/fuel-efficiency/alternative-fuels/question105.htm
Chevrolet, S. (2021, March 10). What Is the Difference Between Diesel and Gas? Sweeney Chevrolet. https://www.sweeneychevrolet.com/blog/what-is-the-difference-between-diesel-and-gas/#:%7E:text=Diesel%20fuel%20is%20thicker%20than,fuel%20economy%20than%20gas%20engines.
WHAT’S THAT STUFF? – Asphalt. (1999). Chemical and Engineering News. https://pubsapp.acs.org/cen/whatstuff/stuff/7747scit6.html#:%7E:text=Asphalt%20typically%20contains%20about%2080,several%20hundred%20to%20many%20thousands.