For example, the alkane group contains the ch2 repeating unit. Igcse physical and chemical properties of hydrocarbons. A hydrocarbon homologous series is a series of hydrocarbons which. In organic chemistry, a homologous series is a series of compounds with the same functional group due to the presence of the same functional group, compounds within the same homologous series have similar chemical properties. They also have a similar trend in physical properties. Alkanes form a homologous series and so do alkenes. Homologous series is a series where in the hydrogen atom is replaced by the same functional group in multiple carbon compounds. Order in homologous series photograph shows the first members of various homologous series. Homologous series are chemically similar or chemically the same or. But, alkanes are hydrocarbons, meaning that there are only hydrogen and carbon atoms. A homologous series is a group or family of organic compounds that has certain characteristics. For example, alkane, alkene and alcohol are separate homologous series. A homologous series homos is greek for the same as can be defined as the group of compounds in which the various members have similar structural features and similar chemical properties and the successive members differ in their molecular formula by one methylene ch 2 group.
Homologous series is a series of compounds with similar chemical properties and same functional group differing from the successive member. Chemical properties of alkanes is the last part of the alkanes episodes but this marks the beginning of learning another homologous series,alkenes. This page was last edited on 1 december 2015, at 18. Homologous series grade 11 science notes reference notes. Files are available under licenses specified on their description page. Covalent bonds are formed when atoms share pair of electrons. If the only difference between the molecules is the length of the chain, then that is the only difference that can. When used to forecast the properties of unknown members of the series, the concept of.
So, none of the hydrogen atoms are being replaced by a functional group. What is the homologous series of hydrocarbons what do you mean by homologous series. Homologous series chemistry, class 11, organic chemistry. The boiling points are graphed out to show the gradation of physical properties within an homologous series of compounds. Hydrocarbons are chain molecules of varying lengths made from hydrogen and carbon atoms only, joined together by covalent bonds. S12 shows the corresponding contour plots of catalyst activity vs. Such organic compounds that vary from one another by a repeating unit and have the same. The graph below shows a smooth increase in boiling point with increasing number of carbon atoms for the first eight straight chained alkanes in the homologous series. Members of a group of compounds, such as the alkanes, that have similar chemical structures and graded physical properties, and which differ from one another by the number of atoms in the structural backbone, are said to constitute a homologous series. The reaction between alkanes and chlorine or bromine. A homologous series is a family of organic compounds that.
Homologous series organic compounds are grouped into different homologous series. Learn homologous series with free interactive flashcards. The combustion of alkanes, including incomplete combustion. Differ by ch 2 in molecular formulae from neighbouring compounds. In the field of organic chemistry, a homologous series is a sequence of compounds with the same functional group and similar chemical properties in which the members of the series can. Homologous series a homologous series is a group of compounds with similar characteristics and the same general formula. These forces govern the physical properties of alkanes such as solubility and boiling. Organic compounds also have functional groups, which define the basic properties of the compound. Explain the properties within and between the homologous series of alcohols with reference to the intermolecular and intramolecular bonding present organic chemistry alcohols alcohols form stronger intramolecular and intermolecular hydrogen bonds. A homologous series is a group of chemicals which have similar chemical properties and can be represented by a general formula. Alkanes in a homologous series have similar chemical properties because the molecules have the same sort of bonds in the same array. Alkanes experiments about physical and chemical properties of alkanes investigating the solubility of hexane in water and the action of some common reagents on hexane i.
Such series are most common among organic compounds, the structural difference being a methylene group. The homologous series is a family or group of hydrocarbons or derivatives having the same functional group, same general formula and similar chemical properties. The series continues in this manner to include ethane c 2 h 6. Natures chemistry homologous series national 5 chemistry. 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.
With their repeated ch 2 units, the alkanes constitute a homologous series of organic compounds in which the members differ in molecular mass by multiples of 14. The alkanes and the alkenes are examples of homologous series of. The homologous series of straight chained alkanes begins methane ch4, ethane c2h6, propane c3h8, butane c4h10, and. An introduction to the alkanes including cycloalkanes and their physical properties. This video explains and illustrates what homologous series are. Carbon chains of varying length have been observed in organic compounds having the same general formula. An homologous series is a group of compounds with similar structural features that can be represented by a general formula whose members differ by one ch 2 unit you can think of an homologous series as a family or group of compounds, whose chemical behaviour is very similar and whose physical properties show trends when ascending the members of the group in terms of. Identify and name simple straightchain alkanes given formulas and write. Homologous series of alkanes, alkenes and alkynes with examples. T, the differences in boiling points and melting points between consecutive members of the homologous series of continuouschain alkanes. Physical properties of alkanes chemistry assignment.
In first year organic chemistry, the first ten names of the homologous series are usually all that need to be memorized. This gradual variation makes it possible to predict properties of a compound from the properties of other members of its homologous series. A homologous series is a group of chemicals which have similar chemical properties. This means that they have similar chemical properties to each other and they have trends in physical properties. They are hydrocarbons and only consist of single bonds. Homologous series homologous series characteristics. A homologous series is defined as a family or group of structurally similar organic compounds all the members of which contain the same functional group, show a gradation in physical and similarity in chemical properties and. Gives example of homologous series alkanes, alkenes and alcoholsand physical properties. Physical properties of alkanes and the concept of homology.
The number of carbons continuously bonded together is an important structural feature and is described using the homologous series. Some examples of homologous series are shown in the following table. Alkanes contain only cc and ch sigma bonds which are almost nonpolar due to very small difference of electronegativity between carbon and hydrogen atoms. All the organic compounds have been divided into different families or group depending upon their structure and chemical properties. A homologous series of alkanes may be formed by adding additional methylene groups ch 2. A group of organic compounds which can be represented by the same general formula with a same functional group and which show more or less similar trends in their properties is known as homologous series.
Under fuel lean conditions excess o 2, pt is superior, and pd is the secondbest catalyst for all alkanes. What is similar about members of the same homologous series. A brief look at cracking alkanes in the oil industry. The members of such a series, called homologs, have properties that vary in a. A fact sheet that was used for an assignment looking at the differences in physical properties of different homologous series related to. Significance and properties of the homologous series. A homologous series is a series of compounds which. Instead of a bewildering array of individual carbon compounds, we can study a few members of a homologous series and from them deduce some of the properties. Homologous series of alkanes, alkenes and alkynes with. The optimal properties o and c binding energies are the same for all alkanes providing support to the homologous series concept. Such series are most common among organic compounds, the structural difference being a methylene group, as in the paraffin hydrocarbons, or alkanes.
Because alkanes only contain carboncarbon single bonds and carbonhydrogen bonds they are all going to behave in the same way. They have similar chemical properties because chemical properties depends on bonding. The alkanes, alkenes and cycloalkanes are examples of homologous series. This means that they have similar chemical properties to each other and they have trends in physical. The defining characteristic of a homologous series is a repeating unit. In the field of organic chemistry, a homologous series is a series of compounds with the same functional group and similar chemical properties in which the members of the series can be branched or unbranched this can be the length of a carbon chain, for example in the straightchained alkanes paraffins, or it could be the number of monomers in a. A homologous series of alkanes may be formed by adding additional methylene. Properties of homologous series definition, examples. Homologous series is a series of compounds with similar chemical properties and same functional group differing from the successive member by ch 2. All structured data from the file and property namespaces is available under the creative commons cc0 license. Explain the properties within and between the homologous.
Physical properties of alkanes are consistent with their chemical structure. Alkanes alkanes and alkenes gcse chemistry single science. The alkanes are a homologous series of hydrocarbons. Homologous series wikimili, the best wikipedia reader. Chemicals in the same homologous series will show a gradual variation in one property eg. In the field of organic chemistry, a homologous series is a series of compounds with the same functional group and similar chemical properties in which the members of the series can be branched or unbranched. Why do alkanes in an homologous series have similar. Homologous series, any of numerous groups of chemical compounds in each of which the difference between successive members is a simple structural unit. Homologous series is defined as a systematic order of organic compounds having same functional group that can be represented by same general formula and prepared by same method.
The homologous series of straightchained alkanes begins methane ch4, ethane c2h6, propane c3h8, butane c4h10, and. Hydrocarbons are compounds that contain only hydrogen and carbon. Choose from 352 different sets of homologous series flashcards on quizlet. Alkanes, alkenes, alcohols, carboxylic acids and esters belong to different homologous series. A homologous series of alkanes may be formed by adding additional. The difference between two consecutive members in their composition is ch 2 unit. For example, the boiling points of the alkanes increase down the series, so that the first four members are gases at room temperature and standard pressure. Homologous series definition a homologous series is a group of organic chemical compounds, usually listed in order of increasing size, that have a similar structure and hence, also similar properties and whose structures differ only by the number of c h 2 units in the main carbon chain. The organisation of organic compounds into the various different homologous series makes the study of organic chemistry more systematic, orderly and effective. It makes use of 3d modelling in considering how the general formula of an homologous series. This means that the compounds are identical with the exception of the number of ch2 units in the compound.
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