Is the tar from tabacco that goes into smokers’ lungs, related in molecular structure to the tar that is used on roads? Why do we call them both tar?
The tar that is used in road building is usually bitumen; the less-volatile hydrocarbon fractions of crude oil - the bits left over when the gas, petroleum, kerosene, etc has been distilled off.
The tar from tobacco smoke is actually pretty much condensed smoke - it’s the non-volatile products of combustion of plant material - in this case tobaco smoke, but you can get the same sort of result from burning more or less any plant material. It is quite significantly composed of hydrocarbons, but these will not be exactly the same, or at least present in the same proportions as those in bitumen.
But crude oil is the fossilised remains of plants and animals, so I guess you could say that there is a relationship in terms of origins; they both came from living things (unless you happen to subscribe to the hypothesis of abiogenetic oil formation, which is certainly not universally true and is at best rather speculative at present).
The city of Austin recently banned coal tar sealants for asphalt (in parking lots, at least), partly because of the health risk from polycyclic aromatic hydrocarbons, which are one of the known carcinogens in cigarette smoke. So they have that in common, anyway.
Thanks guys