In chemistry, a homologous series is a series of organic compounds with a similar general formula, possessing similar chemical properties due to the presence of the same functional group, and shows a gradation in physical properties as a result of increase in molecular size and mass see relative molecular mass. Choose a functional group aldehyde, carboxylic acid, ketone, amine, or alcohol. Ways to identify homologous series are discussed as well as the chemical and physical properties of. Even though members of the same homologous series generally have similar chemical properties there may still be trends through the group e. Jun 12, 2017 the order in the physical and chemical properties of organic molecules in a homologous series makes it easy to predict the properties and behaviour of unknown members of the series. They are compounds with alkyl radicals with halogen atom or even atoms as their functional group. Homologous series wikimili, the best wikipedia reader. Changes in physical properties in homologous series. As all members of the same series have the same functional groups, then the chemical properties are similar. In this video lecture, physical properties meltingboiling points, solubility in polar and nonpolar solvents, electrical conductivity, viscousity, flamability etc are discussed in details for.
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. How do physical properties change in a homologous series. Jan 16, 2018 cbse class 10 science carbon and its compounds the family of organic compounds have same functional group, similar chemical properties and their successive member differ by a ch2 group, is. Homologous series of alkanes, alkenes and alkynes with. Carbon and its compounds homologous series youtube. Homologues have similar chemical properties because the functional group of the. The number of carbons continuously bonded together is an important structural feature and is described using the homologous series.
Why do alkanes in an homologous series have similar. The physical properties of various members of a homologous series change regularly with an increase in the molecular mass. A homologous series is a set of organic compounds with the same functional group that vary only by a ch2 group. Alkanes in a homologous series have similar chemical properties because the molecules have the same sort of bonds in the same array. Each member of homologous series is called homolog. These properties typically change gradually along the series, and the changes can often be. Apr 18, 2010 other than sharing the same general formula, what are 2 other features of members of the same homologous series. These compounds have similar chemical properties due to the addition of same kind of functional group throughout the chain. Physical properties change in a homologous series but chemical properties remain almost the same because the functional group does not change.
A homologous series in organic chemistry is a group of organic compounds compounds that contain carbon c atoms that diverge from each other by one methylene ch 2 group. Alkanes, alkenes, alcohols and carboxylic acids are different homologous series of organic compounds. Variation of some physical properties in a homologous series of hydrocarbons are described below. A homologous series is a family of organic compounds that. The first four alkanes in the homologous series retain their original names. Within a given homologous series the chemical properties of the compounds are essentially all alike, and the physical properties vary in a continuous and predictable manner. Homologous series of inorganic compounds include the phosphoric acids, the silicic acids, and the phosphonitrilic chlorides. 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. Within a given homologous series the chemical properties of the compounds are essentially all alike, and the physical properties vary in a continuous and. What is the difference between functional group and. In first year organic chemistry, the first ten names of the homologous series are usually all that need to be memorized. Homologous series functional groups and isomerism, chemistry tutorial. Choose from 352 different sets of homologous series flashcards on quizlet. Some of the similarities can be the length of a carbon chain as in the case of straightchained alkanesparaffins or the number of monomers in.
What are the physical and chemical properties of homologous. Significance and properties of the homologous series gulpmatrix. By studying the properties of a few members of a homologous series, it is possible to deduce the properties of the other members in the same series. In first year organic chemistry, the first ten names of the homologous series. Heya mate here is your answer in 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 differ by the number of repeating units they contain. For example, alkane, alkene and alcohol are separate homologous series. Homologous series is a series of compounds with similar chemical properties and same functional group differing from the successive member. 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 ch 2 units in the main carbon chain.
There is a gradation in the physical properties of the homologues of the series due to the increasing length of the carbon chain. Homologous series homologous series characteristics. 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. 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. How do physical properties change in a homologous series of. As the molecular mass increases in any homologous series, a gradation in physical properties is seen. Homologous series are referenced frequently in organic chemistry, where compounds can differ by the length of their carbon chain. In chemistry, a homologous series is a series of organic compounds with a similar general formula, possessing similar chemical properties due to the presence of the same functional group, and. Cbse ncert notes class 10 chemistry carbon and its compounds. In organic chemistry, a functional group is a specific arrangement of atoms that confers specific chemical properties to the rest of the molecule. Melting and boiling points of hydrocarbons in a homologous series increase with an increase in molecular mass. Find data for each member of your homologous series. Other than sharing the same general formula, what are 2 other features of members of the same homologous series.
When used to forecast the properties of unknown members of the series, the concept of. Ch 3 oh methyl alcohol methanol ch 3 ch 2 ch 2 oh propyl alcohol. 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. For example, the series of primary straightchained alcohols has a hydroxyl at the end of the carbon chain. A functional group is an atom, a radical group of atoms or a bond common to a homologous series, and which determines the main chemical properties of the series. Halogenoalkanes are a homologous series in the organic chemistry. 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. In chemistry, a homologous series is a series of organic compound s with a similar general formula, possessing similar chemical properties due to the presence of the same functional group, and shows a gradation in physical properties as a result of increase in molecular size and mass see relative molecular mass. The physical propertieslike solubility, melting point, boiling point, state of members of a homologous series either gradually increase or decrease with increase in molecular mass. A homologous series is a family of hydrocarbons with similar chemical properties who share the same general formula.
The members of a particular homologous series have almost same chemical properties due to presence of same functional group. For example, the boiling points of the alkanes increase down the series, so that the first. In chemistry, a homologous series is a series of compounds with the same general formula, usually varying by a single parametersuch as the length of a carbon chain. Naturally occurring and synthetic polymers can be formed from a variety of monomers. The physical properties of the members change gradually as the number of carbon atoms per molecule increases. Homologous series are referenced frequently in organic chemistry, where. Homologous series innoclazz academy banglorefind the. Hydrocarbons are compounds that contain only hydrogen and carbon. Those data are not readily available, but a quick experiment will verify it. Methane, ethane, propane, butane and so on is a homologous. The chemical properties of the members of an homologous series are due to the presence or lack of functional groups.
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. For example, the oh group, when attached to a saturated carbon, makes the parent molecule an alcoho. 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. 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. Homologous series are groups, or families, of organic compounds that contain the same functional groupings and whose members differ by. 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. This means that they have similar chemical properties to each other and they have trends in physical properties.
Series of compounds in which the same functional group substitutes for hydrogen in a carbon chain is called a homologous series. Homologous series, in chemistry can be defined as a series of organic compounds with a similar general formula, possessing similar chemical properties due to the presence of the same functional group, and shows a gradation in physical properties as a. For example, ethane has a higher boiling point than methane since it has more van. Jan 30, 2018 in organic chemistry, a functional group is a specific arrangement of atoms that confers specific chemical properties to the rest of the molecule. A homologous series is a series of compounds exhibiting the same chemical properties as they belong to the same functional group. Each member of your lab group needs to choose a different functional group. 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 any two adjacent members of which differ by a ch 2 group. Learn homologous series with free interactive flashcards.
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 ch 2 units in the main carbon chain 1. For example, the compounds given below belong to the alcohol family. The alcohols which only contain one hydroxyl group attached to a saturated carbon form a homologous series. Common functional groups and their families of compound. There are three types of halogenoalkaes, they are primary, secondary and tertiary halogenoalkanes. A series of carbon compounds in which same functional group substitutes the hydrogen atom is called a homologous series. 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. Properties of homologous series definition, examples. Homologous series of alkanes, alkenes and alkynes with examples. 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. 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. The homologues in a homologous series undergo similar chemical reactions because they have the same functional group. Why do members of the same homologous series show similar. Compounds within a homologous series typically have a fixed set of functional groups that gives them similar chemical and physical properties.
Jan 10, 2018 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 any two adjacent members of which differ by a ch 2 group. Homologous series grade 11 science notes reference notes. All the members of a homologous series have same chemical properties due to same functional. The order in the physical and chemical properties of organic molecules in a homologous series makes it easy to predict the properties and behaviour of unknown members of the series. Features include a general formula and neighbouring members differing by ch2, with similar chemical properties and with a gradation in physical properties. Other physical properties such as solubility in a particular solvent also show a similar gradation. Significance and properties of the homologous series. For example, methane, ethane, and propane are part of a homologous series. This will count as a lab grade a homologous series is a set of organic compounds with the same functional group that vary only by a ch2 group.
Igcse physical and chemical properties of hydrocarbons. Physical properties physical properties of the members of a homologous series vary with the increase in atomic weight. Homologous series chemistry, class 11, organic chemistry. Methods of preparation generally all the members of a series can be prepared by using same method. The lower members of the homologous series are gases at room temperature. The physical properties like solubility, melting point, boiling point, state of members of a homologous series either gradually increase or decrease with increase in molecular mass. Differ by ch 2 in molecular formulae from neighbouring compounds. This lesson covers the definition of a homologous series of molecules in organic chemistry. Homologous series, in chemistry can be defined as a series of organic compounds with a similar general formula, possessing similar chemical properties due to the presence of the same functional group, and shows a gradation in physical properties as a result of increase in molecular size and mass. Notes on functional group and homologous series grade 11. Carbon chains of varying length have been observed in organic compounds having the same general formula. The homologous series is a family or group of hydrocarbons or derivatives having the same functional group, same general formula and similar chemical properties.
Properties of homologous series definition, examples, diagrams. Homologous series is a series of compounds with similar chemical properties and same functional group differing from the successive member by ch 2. This is because the melting points and boiling points increase with increasing molecular mass. Sep 23, 2016 in this video lecture, physical properties meltingboiling points, solubility in polar and nonpolar solvents, electrical conductivity, viscousity, flamability etc are discussed in details for. Natures chemistry homologous series national 5 chemistry. A homologous series is a family of organic compounds containing a particular characteristic group and exhibiting similar properties. They also have a similar trend in physical properties.
Solubility of the homologous series of linear nalkanols in water at the same time, the solubility of this homologous series of alcohols increases in nonpolar solvents like hexane and benzene. A hydrocarbon homologous series is a series of hydrocarbons which. If the only difference between the molecules is the length of the chain, then that is the only difference that can. All the members of a homologous series have same chemical properties due to same functional group. 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. The difference between two consecutive members in their composition is ch 2 unit. Chemical properties all the members of a homologous series have same chemical properties due to same functional group.
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