Alkanes are not very reactive and have little biological activity. Alkanes are used to prepare black carbon, water gas, alkyl halides, alcohols, and aldehydes, they are homologous series as each compound exceeds the previous one by ch 2 group, they have a general molecular formula, the same chemical properties and graduated in physical properties, liquid and gaseous alkanes are used as fuel. Solubility in nonpolar solvents, such as ether and acetone, is extensive. Journal of chemical information and computer sciences 1996, 36 4, 844849.
Since there is very little difference between the electronegativities of carbon and hydrogen, alkanes are almost nonpolar. Hydrogenation is used in the manufacture of margarine from vegetable oils. Chemical properties of alkanes what are examples of alkanes. Therefore, it is very difficult to break their bonds, unless they are heated to fairly high temperatures. The simplest of the functional groups are the hydrocarbons, which include the alkanes, alkenes, alkynes, and aromatic hydrocarbons. Due to very little difference of electronegativity between carbon and hydrogen and covalent nature of cc bond or ch bond, alkanes are generally nonpolar molecules. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in which all the carboncarbon bonds are single. Properties of alkanes alkanes are organic compounds that consist entirely of singlebonded carbon and hydrogen atoms and lack any other functional groups. It deals with their formulae and isomerism, their physical properties, and an introduction to their chemical reactivity. The product is an alkane having the same carbon skeleton as the alkene. Sep 28, 2019 we are doing hydrocarbon of organic chemistry. Since these bonds are quite strong, alkanes are the least reactive of all the hydrocarbons. Properties of alkanes alkanes are the simplest organic molecules, consisting of only carbon and hydrogen and with only single bonds between carbon atoms. The viscosity of liquid alkanes increases as the number of carbon atoms increase.
The reaction occurs at a convenient rate only in the presence of. Alkanes are quite inert substances with highly stable nature. Alkenes on the other hand have carbondouble bondstwo carbon d. Molecular modeling of the physical properties of alkanes. The alkanes range in complexity from the simplest case of methane. Alkanes formula, definition, structure, properties, videos. Two important reactions that the alkanes do undergo are combustion and halogenation. Alkenes react with a much richer variety of compounds than alkanes. Alkynes are generally nonpolar molecules with little solubility in polar solvents, such as water. The characteristic reaction of alkanes is substitution. Physical properties of alkanes organic chemistry tutorial. Alkynes have higher boiling points than alkanes or alkenes, because the electric field of an alkyne, with its increased number of weakly held. Since alkanes consist exclusively of carbon and hydrogen held together by single.
Jan 26, 2016 alkanes have simple carbon bonds, low melting and boiling points as well as low viscosity. Using standard conditions 25 o c, 1atm, alkanes up to 4 carbons i. Physical properties of alkenes are quite similar to those of alkanes. Since only c and h atoms are present, alkanes are nonpolar. Alkanes, c412 c5h14 cid 94630 structure, chemical names, physical and chemical properties, classification, patents, literature, biological activities, safety. The unbranched alkanes methane, ethane, propane, and butane are gases. Neither positive ions nor negative ions are attracted to a nonpolar molecule.
Chemical properties of alkenes chemistry assignment. Jun 15, 2017 the data in table shows the physical properties of the first ten straightchain alkanes. Properties and uses of alkanes chemistry tutorial key concepts. Physical properties of alkanes alkanes are nonpolar only dispersion forces act between molecules. Alkynes resemble the alkenes and alkanes in physical properties. Oct 25, 2014 alkanes and alkenes do not react as follows. Chemical properties of alkane carbon compound duration. Alkynes have a higher melting point than the alkanes and alkenes. Boiling points, melting points, and densities generally increase with the size of the alkane. Physical properties of alkane carbon compound youtube. The physical properties of alkenes and alkynes are generally similar to those of alkanes or cycloalkanes with equal numbers of carbon atoms. This is because carboncarbon cc and carbon hydrogen ch bonds are quite strong since carbon and hydrogen atoms have nearly the same electronegativity values. Alkanes are very stable because the ch and cc double bonds are relatively stable and difficult to break. The alkanes from pentane through to c 16 are liquids with the remainder larger molecules being solids.
The ultimate products of this reaction are alkanes. In organic chemistry, an alkane, or paraffin a historical name that also has other meanings, is an acyclic saturated hydrocarbon. Some important chemical reactions of alkanes are discussed below. Because alkanes have relatively predictable physical properties and undergo relatively few chemical reactions other than combustion, they serve as a basis of comparison for the properties of many other organic compound families.
The properties of alkynes pretty much follow the same pattern of those of alkanes and alkenes. By the time you get 17 carbons into an alkane, there are unbelievable numbers of isomers. Chemical properties of alkanes what are examples of. Hydrogenation is the addition of molecular hydrogen h 2 to a multiple bond, which converts alkenes to alkanes. Chemical properties of alkanes chemistry libretexts.
They are only composed of carbon and hydrogen no other molecule. Physical properties, chemical properties, and uses of alkane hydrocarbons tutorial for chemistry students. Due to their low boiling points, lower alkanes are highly volatile. Alkanes vary with the molecular weight and the molecular structure. All alkynes are odourless and colourless with the exception of ethylene which has a slight distinctive odour. Aug 31, 2018 alkanes are used to prepare black carbon, water gas, alkyl halides, alcohols, and aldehydes, they are homologous series as each compound exceeds the previous one by ch 2 group, they have a general molecular formula, the same chemical properties and graduated in physical properties, liquid and gaseous alkanes are used as fuel. Among alkanes volatility decreases with increase in chain length. Alkanes are immiscible in water but freely miscible. Furthermore they have low density and are waterinsoluable. We restore different alkanes while fractional distillation of petroleum. Methane is one of the major components of natural gas.
The molecules that have a lower molecular weight are gases at room temperature and as the molecular weight increases their physical state changes from gas to liquid and then to solids. Hydrocarbons chemical properties of alkanes organic. All liquid alkanes are less dense than water and therefore float on it. Alkanes have simple carbon bonds, low melting and boiling points as well as low viscosity. Lower alkanes c 1 to c 4 are gases, middle one c 3 to c 17 are liquids and higher are solids. Almost all of the chemical reactions of alkene occur at the double bond. The physical properties of alkynes are very similar to those of the alkenes. The first three alkenes are gases, and the next fourteen are liquids. This is because the backbone carbon atoms in alkanes have attained their octet of electrons through forming four covalent bonds the maximum allowed number of bonds under the octet rule.
Physical and chemical properties of alkanes slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Definition and applications to the prediction of physical properties of alkanes. It is because of this relative inertness that alkanes are also called paraffins. Identify the physical properties of alkanes and describe trends in these properties. Today we are going to cover all chemical properties of alkanes in this video. What are the physical and chemical properties of hydrocarbons. Halogens, especially chlorine and bromine add on alkenes readily producing a dihalogen derivatives. This because alkenes are unsaturated hydrocarbons that have a double bond, cc, between two carbon atom. If you continue browsing the site, you agree to the use of cookies on this website. Many functional groups contain oxygen atoms, such as alcohols, ethers, aldehydes, ketones, carboxylic acids, and esters.
Physical properties of alkanes chemistry libretexts. Alkanes have low melting or boiling points because of the very weak intermolecular forces between alkane molecules. Apart from the following three reactions, alkanes can hardly carry out other reactions. Volatility refers to the ability of a liquid to change into vapour state. Alkenes also readily undergo halogenation a reaction in which a halogen reacts at a carbontocarbon double or triple bond to add halogen atoms to carbon atoms. This means that they have similar chemical properties to each other and they have trends in physical properties. Alkane molecules are nonpolar and therefore generally do not react with ionic compounds such as most laboratory acids, bases, oxidizing agents, or reducing agents. Among isomeric alkanes more the branching, greater is the. Chemical properties of alkane carbon compound youtube. Physical properties of alkanes are consistent with their chemical structure. Physical properties of alkanes chemistry assignment. Journal of chemical information and computer sciences 1996, 36 6, 10921097.
Difference between alkanes and alkenes compare the. Hence, the members of the alkane family have closely related properties which vary in a systematic and predictable way. Nothing happens when alkanes are merely mixed with oxygen o 2 at room temperature, but when a flame or spark provides the activation energy, a highly exothermic combustion reaction a chemical reaction in which a substance combines with molecular oxygen to make oxygencontaining compounds of other elements in the reaction. Alkynes have stronger force of attraction than alkanes or alkenes. In fact, the alkanes undergo so few reactions that they are sometimes called paraffins, from the latin parum affinis, meaning little affinity. Oct 07, 2014 it gives the description of chemical and physical properties of alkanes. In the alkane family, each member differs from a previous member only by having an additional ch 2 unit. Alkenes react with a much more compound variety than alkanes. Alkanes are not very reactive when compared with other chemical species. Alkanes are nonpolar molecules so they are more soluble in nonpolar solvents than they are in polar solvents.
Branched alkanes normally exhibit lower boiling points than unbranched alkanes of the same carbon content. All alkanes can be burned, and the reaction exothermic. Igcse physical and chemical properties of hydrocarbons. The alkanes are a homologous series of hydrocarbons. Properties and uses of alkanes chemistry tutorial ausetute. From the physical properties of the alkanes, it can be established that. Alkenes are a family of compounds containing hydrogen and carbon only hydrocarbons with a carboncarbon double bond. There are two main molecular arrangements in alkanes. Alkynes are unsaturated carbon that shares a triple bond at the carbon site. Alkanes are also called as paraffin because these compounds show very low reactivity towards most reagents.
The use of hydrogenation to convert unsaturated vegetable oils to saturated fats is discussed in chapter 17 lipids, section 17. Chemical properties of alkenes linkedin slideshare. The boiling points shown are for the straight chain isomers in which there are more than one figure 1. May 15, 2020 to identify the main chemical properties of alkanes. Physical properties the unbranched alkanes methane, ethane, propane, and butane are gases. Alkenes contain a carboncarbon double bond which changes the physical properties of alkenes. Major sources of alkanes are petroleum and natural gas. What are the differences in chemical properties between. The first four members of straight chain alkanes methane, ethane, propane and butane are gases. Alkanes are less dense than water alkanes float on top of water. Because alkanes have relatively predictable physical properties and undergo relatively few chemical reactions other than combustion, they serve as a basis of.