Examples of such series are the straightchained alkanes paraffins, and some of their derivatives such as the primary alcohols, aldehydes, and monocarboxylic acids. A common example of homologous structures is the forelimbs of vertebrates, where the wings of bats and birds, the arms of primates, the front flippers of whales and the forelegs of fourlegged vertebrates like dogs and crocodiles are all derived from the same ancestral tetrapod. Examples include the wings on butterflies, bats, and birds. For example in ch 4 and c 2 h 6, the difference is ch 2 unit and the difference between c 2 h 6 and c 3 h 8 is also ch 2 unit. All the members of a homologous series can be represented by a common general formula, as they have the same functional group. Any two adjacent homologues differ by ch 2 in their molecular formulae all the compounds of a. The simplest series of compounds in organic chemistry is the alkanes. Jul 02, 20 a homologous series is a series of compounds with a similar general formula, usually varying by a single parameter such as the length of a carbon chain. Cambridge international examinations cambridge international. Significance and properties of the homologous series. This also contains similar general formula and chemical properties. Difference between position isomerism and metamerism definition position isomerism. Introduction the word homologous series and functional groups describe a few of the umbrella principles that assist in the understanding of organic compounds in spite of their large number.
Homologous series meaning in the cambridge english. The general formula of homologous series of alkynes is c n h 2n2. This video is a part of the series for cbse class 10, chemistry demo videos for chapter carbon and its compounds. During sexual reproduction, one chromosome in each homologous pair is donated from the mother and the other from the father.
Homologous series definition of homologous series by. Natures chemistry homologous series national 5 chemistry. A homologous series is a series of compounds, which has the same functional group. What is homologous series explain with an example science. The defining characteristic of a homologous series is a repeating unit. Ch 3 oh methyl alcohol methanol ch 3 ch 2 ch 2 oh propyl alcohol. Homologies definition, the state of being homologous. Covalent bonds are formed when atoms share pair of electrons. The homologous series of straightchained alkanes begins withmethanech 4,ethanec 2 h 6,propanec 3 h 8,butanec 4 h 10, andpentanec 5 h 12. Homologous seriesfunctional groups and isomerism, chemistry.
A series of compounds in which successive members differ from one another by a ch 2 unit is called a homologous series. Position isomerism is the presence of a similar carbon skeleton and functional groups in two or more organic compounds, but the location of the functional groups is. Such series are most common among organic compounds, the structural difference being a methylene group, as in the paraffin hydrocarbons, or. Such organic compounds that vary from one another by a repeating unit and have the same. These structures do not have to look exactly the same, or have the same function. Homologous series, any of numerous groups of chemical compounds in each of which the difference between successive members is a simple structural unit. The same thing can be observed in case of alkenes in which the first member is ethene and the successive members. Give three characteristics which all members of a homologous series share. Every chromosome pair represents a set of homologous chromosomes. Translocation mutation between non homologous chromosomes is not to be confused with crossover between homologous chromosomes or regions of chromosomes. 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.
Each homologous series must have the following four characteristics. It is important that you commit to memory the names of the first 10 straightchain alkanes i. Nov 14, 2016 homologous structures are organs or skeletal elements of animals and organisms that, by virtue of their similarity, suggest their connection to a common ancestor. Homologous structures definition and examples biology. Covalent bonds are formed when atoms share pair of. The most important part, as hinted by their name, is that they are structurally similar. Predict and explain the trends in boiling points of members of a homologous series. Nov 16, 2017 difference between position isomerism and metamerism definition position isomerism. When organic compounds containing same functional group are arranged in series on the basis of their increasing molecular weight, having the difference of ch 2 methylene group in between two consecutive compounds, such series is called homologous series. Chemicals in the same homologous series will show a gradual variation in one property eg. Thus, a functional group is an atom or group of atoms which determine the chemical behavior of an. Compounds within a homologous series typically have a fixed set of functional groups that gives them similar chemical and physical properties.
This means that they have similar chemical properties to each other and they have trends in. Homologous series is a series of organic compounds where the successive members follow a regular pattern. For example, the compounds given below belong to the alcohol family. All the members of homologous series of alkynes have similar structure and similar chemical properties, so they can be grouped together into the homologous series. Such series are most common among organic compounds, the structural difference being a methylene group, as in the paraffin hydrocarbons, or alkanes.
Common examples of homologous structures are the bones in the forelimbs of various vertebrates, such as humans, dogs, birds and. A homologous series is a series of compounds with the same general formula, usually varying by a single parameter such as the length of a carbon chain. A homologous series is a family of organic compounds containing a particular characteristic group and exhibiting similar properties. The homologous series of straightchained alkanes begins methane ch 4, ethane c 2 h 6, propane c 3 h 8, butane c 4 h 10, and pentane c 5 h 12. T he numerous organic compounds can be grouped into a comparatively small number of series or families of compounds known as homologous series. This means that they have similar chemical properties to each other and they have trends in physical properties. For example, the alkane group contains the ch2 repeating unit. Organic compounds consequently tend to be less soluble as an homologous series is ascended. Deletion, the loss of genetic material, and duplication, the. Organic compounds also have functional groups, which define the basic properties of the compound. The members of this series are called homologue and differ from each other by the number of ch 2 units in the main carbon chain.
Hydrocarbons are chain molecules of varying lengths made from hydrogen and carbon atoms only, joined together by covalent bonds. Jan 25, 2020 a translocation mutation is a type of mutation in which a piece of one chromosome breaks off and is joined to another chromosome. Each human cells contain 23 pairs of chromosomes or 46 total. A homologous series is a series of carbon compounds that have different numbers of carbon atoms but contain the same functional group. The most important thing to remember about homologous structures is that they share common ancestry. In chemistry, a homologous series is a group of compounds that share the same basic chemical makeup, but differ in the number of iterations of a certain aspect of their structure. For example, methane, ethane, and propane are part of a homologous series. In a homologous series there is a gradual increase in boiling point as the number of carbon atoms increases. This means that the compounds are identical with the exception of the number of ch2 units in the compound. Give three characteristics which all members of a homologous series. The individual members of a homologous series are called homologues and the phenomenon is called homology. Homologous seriesfunctional groups and isomerism, chemistry tutorial. Following are the characteristics of a homologous series. Thus themolecular massof each member differs by 14atomic massunits.
This video is a part of the series for cbse class 10, chemistry demo videos for chapter carbon and its. An insect population lives along the edge of a northsouth mountain range. A homologous series in organic chemistry is a group of organic compounds compounds that contain c atoms that differ from each other by one methylene ch2 group. Notes on functional group and homologous series grade 11. A homologous series is a group of chemicals which have similar chemical properties and can be represented by a general formula. Information and translations of homologous series in the most comprehensive dictionary definitions resource on the web. Functional groups and homologous series functional groups. Choose from 352 different sets of homologous series flashcards on quizlet. The individual members of a homologous series are known as homologous and the process is. The alkanes are a homologous series of hydrocarbons. The populations from the east and west slope eventually join in a low northern pass and interbreed, producing fertile offspring, but they do not circle around the southern edge because of a desert barrier. In that series, successive members differ in mass by an extramethylene bridgech 2 unit inserted in the chain. In that series, successive members differ in mass by an extra methylene bridge ch 2 unit inserted in the chain.
A homologous series is a group of organic compounds having similar structure and similar chemical properties in which the successive compound differs by ch2 group for example. Homologous series is a series of compounds with similar chemical properties and same functional group differing from the successive member by ch 2. Homologous series are referenced frequently in organic chemistry, where compounds can differ by the length of their carbon chain. Homologous series meaning in the cambridge english dictionary. When an atom or group of atoms bonded to a carbon atom in the chain or ring of an organic compound, shown some characteristic properties of their own, they are termed as a functional group. For example, a chimpanzees arm and a humans arm are homologous structures. The ch 2 group is nonpolar hydrophobic and this increases the percentage of the molecule that is unattractive to water. May 21, 2019 a homologous series in organic chemistry is a group of organic compounds compounds that contain c atoms that differ from each other by one methylene ch2 group. Some examples of homologous series are shown in the following table. A homologous series is a series of organic compounds which belong to the same family i. Whereas homologous structures point to a similar origin and a common ancestor, analogous structures are when animals have similar structures with similar function, but they evolved separately.
A human karyotype shows the complete set of human chromosomes. Homologous series and its characteristics with examples. Common functional groups and their families of compound. Examples of functional groups, homologous series, general formula, displayed formula, graphic formula, molecular formula, skeletal formula, structural formula, empirical formula of molecules etc. 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 homopolymer such as amylose. Explain why the combustion of wood rather than coal can reduce the effect of the emissions. Position isomerism is the presence of a similar carbon skeleton and functional groups in two or more organic compounds, but the location of the functional groups is different from each other. Any two adjacent homologues differ by ch 2 in their molecular formulae all the compounds of a homologous series show similar chemical properties. All members of a homologous series exhibit some common characteristics.
Homologous series of alkanes, alkenes and alkynes with examples. Organic functional groups homologous series explained why. In organic chemistry, a homologous series is a series of compounds with the same general formula, usually varying by a single parameter. The successive members vary from each other by a ch 2 unit. Difference between position isomerism and metamerism. A common example of homologous structures is the forelimbs of vertebrates, where the wings of bats and birds, the arms of primates, the front flippers of whales and the forelegs of fourlegged vertebrates like dogs and crocodiles are all derived from the same. A series of compounds with similar chemical properties, in which members differ from one another by the possession of an additional ch2 group, is called a homologous series. Feb 27, 2019 homologous structures are similar structures in related organisms. All the members of a homologous series can be represented by a general formula. Most of the hydrocarbons in crude oil are hydrocarbons called alkanes. All the compounds of a homologous series show similar chemical properties.
A homologous series in organic chemistry is a group of organic compounds compounds that contain c atoms that differ from each other by one methylene ch 2 group. Since there is a change in the physical properties, we can say that there would be an increase in the molecular size and mass. In biology, homology is similarity due to shared ancestry between a pair of structures or genes in different taxa. For example, methane, ethane, propane, butane, etc. A series of organic compounds in which hydrogen in a carbon chain is replaced by the same functional group, is called homologous series. Carbon chains of varying length have been observed in organic compounds having the same general formula. Homologous series a homologous series is a group of compounds with similar characteristics and the same general formula. Learn homologous series with free interactive flashcards. In other words, only organisms that are somehow related to each other can have homologous structures. The alkanes, alkenes and cycloalkanes are examples of homologous series.
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