A small difference in the molecule changes the name and can drastically change the reactivity of the compound. Physical properties of alkenes chemistry assignment. Comparison of reactivities of alkanes, alkenes and alkynes duration. Alkanes answers to problems 1 c and d are the same.
Alkane molecules are nonpolar and therefore generally do not react with ionic compounds such as most. This holds true for the two compound groups, alkanes and alkenes. For making models of alkanes, you can use toothpicks for bonds and plasticine balls for atoms. Alkanes contain only cc and ch sigma bonds which are almost nonpolar due to very small difference of electronegativity between carbon and hydrogen atoms. The simplest of the functional groups are the hydrocarbons, which include the alkanes, alkenes, alkynes, and aromatic hydrocarbons. Nomenclature structural isomers chain and position isomers free radicals aliphatic alkanes general formula.
The viscosity of liquid alkanes increases as the number of carbon atoms increase. Organic chemistry hydrocarbons alkanes page 1 of 3 organic chemistry is the study of carbon compounds. The table below lists the properties and uses of a number of different alkanes. Pdf organic chemistry made easy for senior secondary schools. Alkane molecules are nonpolar and therefore generally do not react with ionic compounds such as most laboratory acids, bases, oxidizing agents, or reducing agents. Physical properties of alkanes organic chemistry tutorial.
For alkenes and branched hydrocarbons, the geometry of the molecule can be more important than the number of carbons. Volatility refers to the ability of a liquid to change into vapour state. Ppt alkanes and alkenes powerpoint presentation free. Which of the following statements concerning alkanes is correct. Alkanes 2 organic chemistry nowadays almost drives me mad. Alkanes and cycloalkanes 11 million organic compounds which are classified into families according to structure and reactivity functional group fg. This chapter is also available as a downloadable pdf file. Structure of organic compounds an organic compound is a compound made from carbon atoms one or more cs and many hs. Furthermore they have low density and are waterinsoluable. Learn how to recognize the alkane functional group in organic compounds. The names of alkanes containing up to twelve carbon atoms per chain are as follows.
If two molecules can only be interconverted by breaking a bond and then reforming it somewhere else in the molecule, they are structural isomers. Among isomeric alkanes more the branching, greater is the. Mar 02, 2014 the larger alkanes also tend to produce a smokier flame due to incomplete combustion of the alkane molecules. What are the differences in chemical properties between. In organic chemistry, an alkane, or paraffin is an acyclic saturated hydrocarbon. Physical properties of alkanes previous next alkanes contain only carbon and hydrogen atoms. Types of formula general, empirical, molecular, structural, displayed and skeletal. Alkanes are quite inert substances with highly stable nature. Moreover, redox reactions of alkanes involving free radical intermediates. Carbon is unique in the periodic table in that it is the only element that has a whole branch of chemistry dedicated to this study by itself.
You must complete the tests with bromine and potassium permanganate parts c and d above before doing an unknown. Alkanes are saturated hydrocarbons so they are linked by single covalent bonds and these bonds are hard to break thus they are stable and so lesser chemical reactivity is there. Initially, we will be concerned with the physical properties of alkanes. Chemical properties of alkanes alkanes are generally unreactive. They contain no double or triple bonds in their carbon skeletons and, therefore, have the maximum number of carbon to hydrogen covalent bonds. Since there is very little difference between the electronegativities of carbon and hydrogen, alkanes are almost nonpolar. Feb 10, 2011 chemical properties of alkanes 20 m a write chemical equation for complete combustion of methane correct reactant 2m correct product 2m 4. Dealing with organic compounds in chemistry can feel overwhelming. Free online chemical properties of alkanes practice and.
Alkanes naturally occur in crude oil and are a major component of many fuels and solvents derived from petroleum. Properties of alkenes and alkynes no rotation around double and triple bonds similar to alkanes bp and mp isomerism cis and trans. 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. Hydrogenation of alkenes addition of hh h2 to the bond of alkenes to afford an alkane. If you have four different substituents around a double bond cistrans does not work e z nomenclature. All the carbon atoms present in an alkane are \sp3\ hybridized that is, every carbon atom forms four sigma bonds with carbon or hydrogen atoms. Within alkane structure there is free rotation about the carbontocarbon single bonds cc. Alkanes, also called paraffins, are a class of hydrocarbons that are fully saturated with hydrogen. Alkynes are similar to alkenes in both physical and chemical properties.
It is generally observed that evennumbered alkanes have a higher trend in melting point in comparison to oddnumbered alkanes as the evennumbered alkanes pack well in the solid phase, forming a wellorganized structure which is difficult to break. Reactions of alkanes the alkanes and cycloalkanes, with the exception of cyclopropane, are probably the least chemically reactive class of organic compounds. The reaction is highly exothermic, and can lead to an explosion. Boiling points, melting points, and densities generally increase with the size of the alkane. Powerpoint and afl task for teaching alkanes and alkenes. This makes them better fuels, as they release more energy in a combustion reaction.
May 11, 2012 dispersion forces, fractional distillation, combustion and addition reactions. Lower alkanes c 1 to c 4 are gases, middle one c 3 to c 17 are liquids and higher are solids. Determine which class of hydrocarbons alkane, alkene, or alkyne that your unknown belongs to by reacting it with. Properties and uses of alkanes chemistry tutorial ausetute. Write both structural and molecular equations for substitution reaction of methane 5. Within alkane structure there is free rotation about the carbontocarbon single. Alkanes and alkenes physical properties and chemical properties. More than 16,000,000 organic compounds are known, as opposed to about 600,000 inorganic compounds. Physical properties of alkanes chemistry assignment. From the physical properties of the alkanes, it can be established that. Alkanes, cycloalkanes, and functional groups khan academy. The properties of organic molecules depend on the structure, and knowing the names of organic compounds allow us to communicate with other chemists.
However, ignoring financial considerations, alkanes can be prepared from. 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. Kerosene contains c 10 to c 16 alkanes, while heating oil usually involves the c 12 to c 18 range. The alkanes can exist as gases, liquids, or solids at room temperature. Free radicals are the reactive species that participate in the reaction, which usually leads to a mixture of products. Chemical properties of alkanes class 11 notes edurev. The alkanes from pentane through to c 16 are liquids with the remainder larger molecules being solids. Cc single bonds are free to spin around and this leads to different 3d geometries conformers. Fgs behave similarly in every molecule they are part of. Dispersion forces, fractional distillation, combustion and addition reactions.
Chemical properties of alkanes the main chemical property of. First of all, alkanes are the simplest family of hydrocarbons and they form the most basic skeletons from which functional groups are attracted to more complex organic compounds. Learn the iupac system for naming alkanes and cycloalkanes. Well be learning about different aspects of molecular structure, including common functional groups and conformations. Physical properties of alkanes alkanes are nonpolar only dispersion forces act between molecules. Preparation of alkanes from unsaturated hydrocarbons. Reactivity of alkanes properties of alkanes alkenes and alkynes nomenclature isomers preparation of alkenes and alkynes. The physical properties of alkenes are similar to those of the alkanes. Chemical properties of alkanes chemistry libretexts. Alkanes and alkenes physical properties and chemical. Hydrocarbons introduction alkanes isomerism preparation of alkanes physical properties of alkanes reactions of alkanes alkene introduction and isomerism preparation of alkenes physical properties of alkenes reactions of alkenes alkyne introduction, isomerism and preparation physical properties of alkynes reactions of alkynes aromatic.
Alkanes formula, definition, structure, properties, videos. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in which all the carboncarbon bonds are single. Nov 30, 2015 on 17th of november we visited tallinn university of technology in order to investigate a few physical and chemical properties of alkanes. This is because of the effect the precise arrangement of the atoms has on the surface area of the molecule and the ease with which they can pack together.
Methane is one of the major components of natural gas. Among alkanes volatility decreases with increase in chain length. Alkanes are not very reactive when compared with other chemical species. Alkane names, formulas, properties memorize sections 3. The ch bond is weakly polar, due to difference in electronegativity between c and h atoms, however due to the symmetry of ch bonds around the whole alkane, any dipoles are even in size and balance or cancel out. Some salient physical and chemical properties of alkanes are.
Unsaturated hydrocarbons alkenes and alkynes react with h 2 in the presence of finely divided catalysts such as platinum, palladium or nickel to form alkanes. Alkanes are rarely prepared from other types of compounds because of economic reasons. Physical properties of alkanes alkanes are insoluble in water but soluble in organic solvents such as ccl4. Reactions of alkenes ii the addition of h2 to a double bond. They are hydrocarbons and only consist of single bonds. All liquid alkanes are less dense than water and therefore float on it. Alkanes will react with halogens such chlorine gas and bromine water in the presence of ultraviolet light. Alkanes have simple carbon bonds, low melting and boiling points as well as low viscosity. Unsaturated hydrocarbons hydrocarbons with double or triple bondson the other hand, are quite reactive. Even longerchain alkanes are found in lubricating oil, c 15 to c 25 and paraffin wax used for candles and waxed paper, c 23 to c 29. In chapter 7, we noted that alkanes saturated hydrocarbons have relatively few important chemical properties other than that they undergo combustion and react with halogens. Despite their relative inertness, alkanes undergo several important reactions that are discussed in the following section. The larger alkanes also tend to produce a smokier flame due to incomplete combustion of the alkane molecules. Alkane names, formulas, properties memorize sections.
Alkanes and alkenes organic chemistry wyzant resources. Alkenes on the other hand have carbondouble bondstwo carbon d. Chemical reactions of alkanes combustion burning in oxygen. Learn the important physical and chemical properties of the alkanes.
Chemical properties of alkanes 20 m a write chemical equation for complete combustion of methane correct reactant 2m correct product 2m 4. Physical properties of alkanes are consistent with their chemical structure. Densities of alkenes show regular increase with increase in molecular mass. The hydrogen atoms of the alkane are progressively replaced by halogen atoms. They are both hydrocarbons and therefore follow the. Alkanes react with halogens in a socalled free radical halogenation reaction. Apr 03, 2020 chemical properties of alkanes class 11 notes edurev is made by best teachers of class 11.
The unbranched alkanes methane, ethane, propane, and butane are gases. We restore different alkanes while fractional distillation of petroleum. Which of the following is the correct name for this isomer of hexane molecular formula, c 6 h 14. For alkenes, alkynes and aromatic hydrocarbons, spring models can be constructed. On 17th of november we visited tallinn university of technology in order to investigate a few physical and chemical properties of alkanes. However, the maximum density of alkenes is about 0. This document is highly rated by class 11 students and has been viewed 2633 times. Complex organic compounds can perform a number of useful biological functions vitamins, carbohydrates, lipids, proteins, enzymes, atp, dna, rna are all organic compounds which are studied in biochemistry.
Alkanes alkanes are saturated hydrocarbons saturated. This is because the cc bond and the ch bond are relatively strong and so cannot form. Branchedchain alkanes do not exhibit the same smooth gradation of physical properties as do the continuouschain alkanes. Coming from alkanes saturation alkanes are said to be saturated and this means that there are the maximum number of hydrogen atoms attached to each carbon. To me it appears like a primeval tropical forest full of the most remarkable things, a dreadful endless jungle into.
Physical properties, chemical properties, and uses of alkane hydrocarbons tutorial. The melting and boiling points of the shorter chain alkanes is low, but the. Due to their low boiling points, lower alkanes are highly volatile. This is chemical properties of alkanes, section 12.