Caffeine has only one formula: C₈H₁₀N₄O₂ There are, however many, many, many different sources of caffeine; more than 60 plants are known to contain caffeine naturally including coffee beans, tea leaves, and kola nuts.
There are many types of tea. Many teas contain caffeine which can be dangerous for some hyperthyroid patients.
regular, diet, caffeine free
Decaf
As far as I know there is only one kind of caffeine. It is, of course, in many things we consume. Coffee, tea, chocolate, soda drinks (many but not all) contain this substance. The reaction is typical: caffeine is a stimulant. It raised blood pressure, heart rate, can cause shaky hands and heart fluctuations in high doses. The health effects of longtime use are not clear however most studies have not linked caffeine to illness.
Many over-the-counter and behind-the-counter analgesics formulated specifically for headache contain caffeine. In the USA, probably the best known of these is Excedrin. Also, composition tablets known as "Tylenol #1" and "Tylenol #2" in the USA, and as "Compound 222" in Canada, contain caffeine in addition to aspirin and small dosages of codeine. Caffeine arguably works for to relieve certain headaches: those associated with caffeine withdrawal. The efficacy of caffeine in other headache types is controversial.
Somewhere between "none" and "less than 1". Different types of sodas contain different amounts of caffeine, but even "energy drinks" don't contain a full gram of caffeine per serving.
Yes although it probably doesn't have much caffeine in it. Almost all chocolate contains relatively small amounts of caffeine. (By relatively, I mean in comparison to coffee or caffeinated soft drinks which contain a lot of caffeine.)
Caffeine is contained in several plants, especially some plants used to prepare drinks - such as coffee, tee, guarana, yerba mate.
To answer your question on how many hydrogen atoms are there in caffeine, the scientific answer would be 10 atoms of hydrogen.
Tobacco and caffeine are very different as addctive substance or drug. There is no way to compare tobacco to caffeine. Besides being very addictive, smoking is very harmful to our health. Caffeine is a single central nervous system stimulant, on a recommended daily amount. Too much caffeine is not advisable.
Caffeine is C8H10N4O2 and has 10 hydrogen atoms.
The answer is 5,15.1e-4.