Distinguish between smoke and hydrocarbon

Even though you likely see gasoline-powered vehicles everyday, you rarely see what gasoline itself looks like! To the naked eye, gasoline is a pretty uninteresting yellowish-brown liquid. At the molecular level, though, gasoline is actually made up of a striking range of different molecules, most of them hydrocarbons (molecules containing only hydrogen and carbon atoms). Some of the hydrocarbons in gasoline are small and contain just four carbon atoms, while others are much larger and have up to twelve carbons. Some hydrocarbons form straight lines, while others have a branched structure; some have only single bonds, while others have double bonds; and still others contain rings. While the different hydrocarbons in gasoline often have very different properties, such as melting point and boiling point, they all produce energy when they’re burned in an engine. As the gasoline example shows, hydrocarbons come in many different forms. They may differ in length, be branched or unbranched, form linear or ring shapes (or both), and include various combinations of single, double and triple carbon-carbon bonds. Even if two hydrocarbons have the same molecular formula, their atoms may be connected or oriented in different ways, making them isomers of one another (and sometimes giving the two molecules very different properties). Each of these structural features can influence the three-dimensional shape, or molecular geometry, of a hydrocarbon molecule. In the context of large biolo...

[ "article:topic", "alkynes", "alkanes", "saturated", "aromatic", "unsaturated", "addition reaction", "alkenes", "showtoc:no", "Aliphatic hydrocarbons", "hydrocarbons", "aromatic hydrocarbons", "structural formulas", "Condensed Structural Formula", "unsaturated hydrocarbons", "saturated hydrocarbons", "hydrogenation reaction", "license:ccbyncsa", "authorname:anonymous", "program:hidden", "licenseversion:30", "source@https://2012books.lardbucket.org/books/beginning-chemistry" ] Learning Objectives • Identify alkanes, alkenes, alkynes, and aromatic compounds. • List some properties of hydrocarbons. The simplest organic compounds are those composed of only two elements: carbon and hydrogen. These compounds are called hydrocarbons. Hydrocarbons themselves are separated into two types: aliphatic hydrocarbons and aromatic hydrocarbons. Aliphatic hydrocarbons are hydrocarbons based on chains of C atoms. There are three types of aliphatic hydrocarbons. Alkanes are aliphatic hydrocarbons with only single covalent bonds. Alkenes are hydrocarbons that contain at least one C–C double bond, and Alkynes are hydrocarbons that contain a C–C triple bond. Occasionally, we find an aliphatic hydrocarbon with a ring of C atoms; these hydrocarbons are called cycloalkanes (or cycloalkenes or cycloalkynes). Aromatic hydrocarbons have a special six-carbon ring called a benzene ring. Electrons in the benzene ring have special energetic properties that give benzene physical and chemical properties t...

Polycyclic aromatic hydrocarbons (PAHs), produced via incomplete combustion of organics, convey signatures of vegetation burned in the geologic past. New and published burn experiments reveal how the quantity, distributions, and isotopic abundances of fire-derived PAHs were influenced by fuel types, burn conditions, and also phase. PAH concentrations were higher in burn residues from moderate burn temperatures (400–500 °C), and significantly lower in residues from cooler (600 °C) conditions, especially when oxygen was limited. PAH forms tended to be smaller in smoke samples and larger in residues, consistent with molecular physical and chemical properties. Plant functional types were distinguished by relative amounts of retene and dimethyl phenanthrene isomers. Isotopically distinct photosynthetic pathways of the burned material were reflected in the δ 13C values of PAHs, which faithfully captured biomass signatures as well as the ∼12‰ offset between C 3 and C 4 plant types. PAH size, alkylation, and isotope characteristics can differentiate combusted plant types and distinguish between air-borne and sedimentary transport mechanisms. New proxy approaches using PAH amounts, distributions, and isotope signatures can aid and refine interpretations of paleofire ecology in the geologic record. • Previous article in issue • Next article in issue • About ScienceDirect • Remote access • Shopping cart • Advertise • Contact and support • Terms and conditions • Privacy policy We use ...

Smoke occurs when there is incomplete combustion (not enough oxygen to burn the fuel completely). In complete combustion, everything is burned, producing just water and carbon dioxide. When incomplete combustion occurs, not everything is burned. Smoke is a collection of these tiny unburned particles. Each particle is too small to see with your eyes, but when they come together, you see them as smoke. Smoke in a wood fire Wood is made up of: • water • volatile organic compounds – a compound is volatile if it evaporates (becomes a gas) when it is heated • carbon • minerals in the tree’s cells, like calcium, potassium and magnesium (which are non-burnable and become ash). When you put wood on a hot fire, the smoke you see is the volatile organic compounds (hydrocarbons) evaporating from the wood. They start to evaporate at about 149°C. If the fire is hot enough, the hydrocarbons will burst into flames. Once they burn, there is no smoke because the hydrocarbons are turned into water and carbon dioxide. Charcoal After the fire has been burning for a while, most of the hydrocarbons (gases and smoke particles) have been released, and all that is left is charcoal, which is almost pure carbon with some minerals. The hot charcoal slowly burns with a red glow. There are no flames because charcoal will only produce carbon dioxide, which cannot be burned any further, unlike other vapours. Very little smoke is produced at this stage. The quicker a fire is reduced to glowing charcoal, th...

Hydrocarbons make up fossil fuels. One of the main by-products of fossil fuel combustion is 2). The ever-increasing use of fossil fuels in 2 to Earth’s 2 concentrations fluctuated between 275 and 290 parts per million by volume (ppmv) of dry air between 1000 CE and the late 18th century but had increased to 316 ppmv by 1959 and rose to 412 ppmv in 2018. CO 2 behaves as a 2 increase in the atmosphere is a major contributing factor to human-induced climate changeLearn more about climate change. hydrocarbon, any of a class of organic chemical Many hydrocarbons occur in nature. In addition to making up Nineteenth-century chemists classified hydrocarbons as either aleiphar, “fat”) described hydrocarbons derived by chemical aliphatic and aromatic are retained in modern terminology, but the compounds they describe are distinguished on the basis of structure rather than origin. Aliphatic hydrocarbons are divided into three main groups according to the types of bonds they contain: alkanes, alkenes, and alkynes. Alkanes have only single bonds, This classification of hydrocarbons serves as an aid in associating structural features with properties but does not require that a particular substance be assigned to a single class. Indeed, it is common for a molecule to incorporate structural units characteristic of two or more hydrocarbon families. A molecule that contains both a carbon-carbon triple bond and a benzene ring, for example, would exhibit some properties that are characteristi...

When you think of a building structure and it being alight, what do you think of? A tall commercial building with flames leaping out the windows? A smaller house fire? Or maybe a residential apartment building? If you did you are not alone. However, how many of you thought about industrial complexes – Factories, oil pipelines and petrochemical plants? The human mind works such that we think about things we see ourselves or on TV and the truth is we see more of the former types of fire than the latter. However, from a technical perspective, the difference in the two types of fire couldn’t be more pronounced, and how they are treated (both in terms of preventative measures and to extinguish the flames) is as a result, very different. Classes of Fire • Cellulosic Fire (CF) – This kind of fire occurs when the fuel source is comprised primarily of cellulose material such as timber or paper. A fire of this nature has a slow flame and spreads – by comparison – gradually. This type of fire is most common in residential and commercial buildings. When the combustible material burns, it gets hot with temperatures reaching up to 500°C in as little as 5 minutes and can escalate to up to 1100°C. Its radiation value has been measured at 50 kW/m2 (Kilowatt/square meter). • Hydrocarbon Fire (HF) – Hydrocarbon fires are caused by combustible liquid such as oil and gas. Carbon and hydrogen make up hydrocarbons and they do not have affinity for H2O (water). Some examples are petrol, diesel, b...