What is a cigarette?
Most substances that have stimulant qualities, including the nicotine in cigarettes, produce brief feelings of improvement in mood. Once a person is addicted, smoking usually suppresses symptoms of withdrawal, which the smoker then associates with feeling relaxed.Smoking a cigarette A cigarette is a small cylinder of finely cut tobacco leaves rolled in thin paper for smoking. The cigarette is ignited at one end causing the cigarette to smoulder and allowing smoke to be inhaled from the other end, which is held in or to the mouth; in some cases, a cigarette holder may be used, as well. Most modern manufactured cigarettes are filtered , and also include reconstituted tobacco and other additives.
The term cigarette, as commonly used, refers to a tobacco cigarette but can apply to similar devices containing other substances.
A cigarette is distinguished from a cigar by its smaller size, use of processed leaf, and paper wrapping, which is normally white, though other colors and flavors are also available. Cigars are typically composed entirely of whole-leaf tobacco.
Rates of cigarette smoking vary widely throughout the world and have changed considerably since cigarettes were first widely used in the mid-19th century. While rates of smoking have over time leveled off or declined in , a developed. World they continue to rise in developing nations.
Nicotine, the primary psychoactive chemical in tobacco and therefore cigarettes is very addictive half of cigarette smokers die of tobacco-related disease and lose on average 14 years of life.Cigarette use by pregnant women has also been shown to cause birth effects including low birth weight, fetal abnormalities, and premature birth from second hand smoke cigarettes has been shown to be injurious to bystanders,which has led to legislation that has prohibited smoking in many workplaces and public areas.
produces a chemical in other words:
extravaganza, one that, in terms of complexity, is hard to beat. By way of an overview, we begin with the reactant, tobacco leaves. These have so far been shown to contain over 3800 identifiable compounds. In the product, cigarette smoke, the corresponding number is actually 4800, including 2800 that are not derived from the tobacco plant itself, so they must have been formed during the smoking process. Dear chemist, what more could your heart desire?
So that we don’t lose track of our chemical overview in the course of smoking an entire cigarette, it is best that we divide it into a series of zones, in which different processes take place
In the course of the one or two seconds required to draw in the first 35 mL of fresh air, an increasingly negative pressure develops over the entire span from combustion zone to mouthpiece. The greatest pressure changes occur at the edge of the tobacco, next to the paper wrap, where air velocities up to 400 cm/s are achieved which after all is equivalent to 12–19 km/h (8–12 mph).
With the introduction of fresh air, which is rich in oxygen, the temperature rises rapidly in the well-aerated outer layer of the combustion zone, and a bright flaring-up after only 0.1 s makes the highly exothermic oxidation reaction readily visible. In this oxygen rich zone the tobacco burns completely, leaving behind only ash, with a high mineral content.
Drawing in more cold outside air leads, after a second or so, to slight cooling of the outer layer of the combustion zone, and as the hot combustion gases are drawn to the center, there occurs a warming of the inner zone, leading overall to a rather complex temperature-distribution pattern
A temperature maximum is achieved along the central axis, 10–12 mm behind the combustion front. There, and in the adjoining heated pyrolysis zone, an oxygen deficiency prevails, and in this reducing atmosphere the vegetable matter carbonizes. Organic compounds released undergo endothermic dehydration, decarboxylation, dehydrogenation, and cleavage.
Solid, liquid, and gaseous material formed during carbonization is drawn into the contiguous distillation zone, where it may precipitate as particles or droplets
Depending on one’s smoking habits, 30–60 seconds may elapse between puffs. During this time, no oxygen is supplied to the tobacco charge, and the combustion zone remains dark, though carbonization processes continue.
Cigarette smoke contains over 4,000 chemicals, including 43 known cancer-causing (carcinogenic) compounds and 400 other toxins. These include nicotine, tar, and carbon monoxide, as well as formaldehyde, ammonia, hydrogen cyanide, arsenic, and DDT. Nicotine is highly addictive.