A homologous series is a series of organic compounds which belong to the same family i. Even though the general formula remains constant in a homologous series, specific members of the series may have different structures or entirely different properties, though qualitatively, reactivity usually remains the same. Homologous series are referenced frequently in organic chemistry, where compounds can. The simplest algebraic formula of a member of a homologous series. Specific naming system used to give unambiguous names to compounds. The definitions at the back of the ocr as chemistry textbook 1 25. 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. In the case of many foreign shares, one series may be owned only by citizens of the country in which the stock. The other part of the definition is that everything in an homologous series must have the same functional group. Alkanes organic compounds ocr gateway gcse chemistry. It is defined as the series of similarly constituted compounds in which the members possess same functional group and has similar chemical characteristics and the two consecutive members differ in their molecular formula by ch 2 group. The main functional groups for as chemistry are shown below.
Homologous series financial definition of homologous series. Corresponding or similar in position, value, structure, or function. Chemistry definitions ocr a level flashcards quizlet. 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. Information and translations of homologous series in the most comprehensive dictionary definitions resource on the web. Homologous series of alkanes, alkenes and alkynes with examples. Functional groups organic chemistry alevel revision world. An homologous series is a family of compounds that all contain the same functional groups and differ in successive members by one ch2 unit. For example, the general formula of the alkanes is. When studying reactions of a homologous series, the alkyl group is relatively unimportant it is the functional group that reacts. It will be very hard to answer all the questions in the paper without knowing these key terms and definitions.
What is an alkane and what is an homologous series. Homologous series is a series of compounds with similar chemical properties and same functional group differing from the successive member by ch 2. In chemistry, a homologous series is a series of compounds with a similar general formula, possessing similar chemical properties due to the presence of the same functional group. Activation energy the minimum energy required to start a reaction by the breaking of bonds. Alevel chemistryocrchains, energy and resourcesbasic concepts and hydrocarbonsalkanes. The definitions at the back of the ocr as chemistry textbook 51 75.
Definition of homologous chromosomes worth 3 marks the. Homologous series alevel chemistry aqa, ocr, edexcel. Naming branched chain alkanes homologous series national. Iupac nomenclature for systematic naming of compounds. Level 1 1 25 chemistry as level ocr definitions memrise. This means that their atoms can be arranged differently to make slightly different compounds with different properties. Why many different homologous series of organic compounds and. Definitions required for the 20 f322 chemistry exam. Ocr a level chemistry a delivery guide organic chemistry. Here are all the chemistry key terms and definitions at revision universe. 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. In biology, homology is similarity due to shared ancestry between a pair of structures or genes in different taxa. 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.
During sexual reproduction, one chromosome in each homologous pair is donated from the mother and the other from the father. Homologous pairs of chromosome are homologous chromosomes only a feature of meiosis. The compounds of each homologous series especially the middle members are characterized by relatively regular changes in certain physical properties. A homologous series is a family of hydrocarbons with similar chemical properties who share the same general formula. Hydrocarbon is a compound consisting of hydrogen and carbon only molecular formula. Homologous series means that the series has the same general formula and the compounds have similar properties and structure, differing only in the number of ch 2 units in the chain. Identify the homologous series to which the compound shown below belongs. Homologous chromosomes definition of homologous chromosomes. Why many different homologous series of organic compounds. Information and translations of homolog in the most comprehensive dictionary definitions resource on. Homologous series a series of organic compounds with the same functional group and the same general formula with each successive member differing by ch2. Natures chemistry homologous series national 5 chemistry.
Every chromosome pair represents a set of homologous chromosomes. 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. As implied in this definition, many cladists consider secondary homology to be synonymous with synapomorphy, a shared derived character or trait state that distinguishes a clade from other organisms. The actual number of atoms of each element in a molecule. Such as having the full definition of a mole rather than just stating that it is a unit for amount of a substance. Two adjacent members of homologous series differ by ch2 online chemistry tutorial iit, cbse chemistry, icse chemistry, engineering and medical chemistry entrance exams, chemistry viva, chemistry job interviews.
Chemistry key terms and definitions revision universe. Written by teachers for the cie igcse chemistry course. As it happens alkanes dont have a functional group what they share is a lack of a functional group. Ocr definitions chains, energy and resources flashcards. Homologous series are often named for their first member for example, methane series, ethylene series, and so on. Ocr a level chemistry definitions a quiz stats by thesetay. For example, methane, ethane, propane, butane, etc. Alevel chemistryocrchains, energy and resourcesbasic. Deletion, the loss of genetic material, and duplication, the. C2 chemistry 214 full word and definitions list for ocr a2 chemistry acid dissociation constant, k a acidbase pair a pair of two species that transform into each other by gain or loss of a proton. A human karyotype shows the complete set of human chromosomes.
A homologous series is a series of carbon compounds that have different numbers of carbon atoms but contain the same functional group. From wikibooks, open books for an open world explain with an example. The enthalpy change when one mole of a substance reacts completely with oxygen under standard conditions, all reactants and products being in their standard states. Start studying ocr definitions chains, energy and resources. Compounds in each series typically have a similar group of atoms called a functional group. Each human cells contain 23 pairs of chromosomes or 46 total. This is a series or family of organic compounds that have similar features and.
Homologous series synonyms, homologous series antonyms. Learners will be expected to know the names of the first ten members of the alkanes homologous series and their corresponding alkyl groups. Secondary homology is implied by parsimony analysis, where a character state that arises only once on a tree is taken to be homologous. Here are is all the jargon you need to know in order to understand chemistry at. This is a series or family of organic compounds that have similar features and chemical properties due to them having the same functional group. This lesson covers the definition of a homologous series of molecules in organic chemistry. Written up definitions for all the topics covered in ocr chemistry a f321 for anyone doing some last minute revision i was doing this as part of my own revision, helpful revision is the best kind, right. Homologous series of alkanes, alkenes and alkynes with.
A series of organic compounds with the same functional group and the same general formula with each successive member differing by ch2. 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. Carbon chains of varying length have been observed in organic compounds having the same general formula. Homologous series definition in the cambridge english. Homologous definition of homologous by medical dictionary. In todays video well discuss the concept of homologous series. Learn vocabulary, terms, and more with flashcards, games, and other study tools. The alkanes, alkenes and cycloalkanes are examples of homologous series. Homologous series cie igcse chemistry revision notes. A homologous series is a group of chemicals which have similar chemical properties and can be represented by a general formula. The term homologous series is explained with a general definition or. The functional group is the atom or atoms in a molecule where most reactions happen. Homologous series article about homologous series by the. Homologous definition and meaning collins english dictionary.
A homologation reaction is a chemical process that converts one member of a homologous series to the next member. Homologous definition of homologous by the free dictionary. Level 3 51 75 chemistry as level ocr definitions memrise. Homologous definition, having the same or a similar relation.
Functional groups chemistry alevel revision revision science. Definition of homologous series in the definitions. They are compatible for all exam boards including igcse. All the compounds within a homologous series have the same general molecular formula and the same functional group carboncarbon, hydroxyl, carboxyl, ester, etc. 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. Ways to identify homologous series are discussed as well as the chemical and physical properties of. Written up definitions for all the topics covered in ocr chemistry a f321 for. Homologous series are referenced frequently in organic chemistry, where compounds can differ by the length of their carbon chain. Homologous chromosomes refer to a pair of chromosomes that have genes for the same traits at corresponding chromosomal locations. Homologous series groups of related having the same chemical functions and the same type of structure organic compounds that differ from one another only by one or more methylene ch2 groups. With so many isomers possible, it is important that each has an individual name. So part of the definition of an homologous series is that its successive members differ by ch 2. Homologous series definition of homologous series by. Like other homologous series, the alkanes show isomerism.
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