Why there are different grades of Gas and the differences.
In: Chemistry
Gasoline is a liquid that’s a mix of “hydrocarbons” – a chemical that has hydrogen and carbon in it. There’s really light hydrocarbons like the butane in your lighter or the propane in your barbecue, and really heavy, solid hydrocarbons like the tar on your roof. Gasoline is in the middle of the bunch.
Each type of hydrocarbon molecule has a certain number of carbon atoms in it, and a certain number of hydrogen atoms. Propane has 3, and butane has 4, for example. And the less the number of carbon atoms, the faster it burns – this is why propane tanks can explode – but that comes with a lower amount of burning energy.
Gasoline is a mix of octane (8 carbon atoms) and nonane (9), and your car’s or lawn mower’s engine is specifically designed to best use a certain mix percentage of those two chemicals. Most cars love “regular” but special smaller motors often work best with “Premium” grade. Premium has a higher percentage of Octane compared to other hydrocarbons in it (that’s the number like 87 or 89 that you see on the pump – that means 87% octane or 89% octane – and premium used to be called “high-octane” for this reason.). Gas stations generally sell less of it, so they charge a little extra for it.
It goes the other way too, with some fuels having much more carbon in their molecules – diesel is a special fuel for a special type of engine that works with much bigger hydrocarbon molecules. It’s more energy-dense, and so is really good for big engines like transport trucks.
Latest Answers