Kerosene and diesel are made up of long, flammable hydrocarbon molecules derived from crude oil, which is also known as petroleum. Kerosene is made up of a mixture of carbon chains with between six and 16 carbon atoms per chain. Diesel fuels are heavier, with anywhere from eight to 21 carbon atoms per chain. Both are liquid at room temperature, but diesel fuel has a higher boiling point.
While other options like biodeisel and gas-to-liquid diesel exist, the predominant form of diesel fuel used is petroleum diesel. It is produced by the fractional distillation of crude oil at temperatures between 392 and 662 degrees Fahrenheit. The molecules that make up kerosene have boiling points between 302 and 572 degrees Fahrenheit. The difference in boiling points is what allows the distillation of petroleum into its constituent molecules and is the chief distinguishing characteristic between the various products.
The fuels that make up gasoline are made up of chains with between 4 and 12 carbon atoms. They all vaporize at temperatures below the boiling point of water, which is why gasoline evaporates so fast when spilled on the ground. The lightest hydrocarbon derived from petroleum is methane, which has only one carbon atom. Methane remains in gaseous form all the way down to -161 degrees Fahrenheit.