Organic compounds contain carbon and hydrogen. Organic compounds which contain only carbon and hydrogen are defined as Hydrocarbons. Many organic compounds contain nitrogen, oxygen, halogens, sulfur, phosphorus which are derived from replacing one or more hydrogen atoms in their molecules with these atoms. Hydrocarbons and their derivatives have different physical and chemical properties.
In this tutorial, first we present different organic compounds and then discuss about basics of organic chemistry.
You can see, only one carbon and four hydrogen atoms include in methane molecule. Four hydrogen atoms are bonded to carbon by single bonds.
Carbon, hydrogen and oxygen include in ethanol. Ethanol has different physical and chemical properties than methane. Ethanol react with Na, but methane doesn't.
Following organic compounds are typical organic compounds and each of those chapters are discussed under these topics physical properties, reactions, IUPAC names, and how to draw isomerism and occurrence of organic compounds.
Carbon takes the noble gas configuration only by sharing electrons with other atoms and it forms covalent bonds. Therefore, a carbon atom forms four covalent bonds in its compounds. As a example, carbon atom in the methane molecule share its four electrons with four hydrogen atoms to form four covalent bonds.
We can represent organic molecule in different ways. If we want to represent ethane(contains two carbon atoms and six hydrogen atoms) molecule we can draw its structure or give number of carbon and hydrogen atoms includes in the molecule such as C2H6 or CH3CH3.
There are two carbon atoms and six hydrogen atoms in ethene molecule. A single bond exists between two carbon atoms and three hydrogen atoms are attached to one carbon atom. Molecular formula of ethane can be written as C2H6.
To represent covalent bonds, straight lines are used. For representing
single bond > one straight line (C-C)
double bond > two straight lines parallelly (C=C)
double bond > two straight lines parallelly (C≡C)
Isomerism are defined as having same molecular formula but their structures are different. There are two isomerism types as structural isomerism and stereoisomerism.
Physical and chemical properties depend on the structure of the molecule. As a example, we can consider molecular formula C2H6O, to understand this change. C6H6 can be ethanol or dimethyl ether.
Dimethyl ether is a gas in room temperature. Also it does not react with Na. But in room temperature, ethanol is a liquid and reacts with Na to emit H2.
The qualitative analysis of an organic compound involves the detection of all the elements present in the organic compound. Oxygen, nitrogen, sulfur, halogens, phosphorus also present in some compounds. Some examples are shown below.
Organic compound and cupric oxide(CuO) is mixed and heated(burnt). Products are sent through anhydrous copper sulfate(CuSO4) and lime water( Ca(OH)2(aq) ).
This method is called as copper oxide test. If organic compound is volatile liquid or gas, then vapour should be sent through heated CuO and the liberated gases are tested for CO2 and water.
Nitrogen in organic can be tested by two methods.
A pinch of organic compound is heated strongly with soda lime (NaOH + CaO) in a test tube. If NH3 gas evolves, it indicates nitrogen.
Sulphur is an organic compounds can be detected by Lassaigne's test. Sodium extract or Lassaigne solution is used to identify sulphur. The sulphur in the compound reacts with sodium metal to form sodium sulphide (Na2S).
Now The Lassaigne's extract is tested in two parts for following tests.
Polarity is a very important concept when we discuss about properties and structure. We know electrons of the bond are attracted towards the more electronegative atom. Then more electronegative atom of the bond holds a partial negative charge(δ-) and other atom has a partial positive charge(δ+).
Chloromethane is a alkyl halide compound. We know electronegativity of chlorine is higher than carbon. Therefore, chlorine receives a δ- charge and carbon receives a δ+ charge.
Polarity of molecule has effects on melting points, boiling points, solubility and more.
Organic compounds show different types of reactions. Reaction types are decides by the mechanism of reaction or how the reaction happens.
A description of changes occurred in a reaction forming products by reactants is defined as a mechanism of reaction. Important points of mechanism of reaction can be gained by experiments.
All changes of bonds are occurred in a single step.
Reactants are converted into intermediate products first. These intermediate products are unstable and quickly participate to the next steps of reaction and give final products.
More than one million compounds were found so far.
In human body contains organic compounds. To explain biochemistry, organic chemistry is used. Also chemistry of food, medicines, textiles, plastic has a significance effect of organic chemistry.
No. There are some organic compounds without hydrogen. CCl4 is an example.
Organic compounds are converted into inorganic compounds using lassaigne's test. Then, testing inorganic anions will tell occurrence of nitrogen and halogens.
Lassaigne's test can be used to identify nitrogen, halogens, sulfur in organic compounds.
The compounds which contain only carbon and hydrogen are defined as hydrocarbons. They are represent by CxHy and x, y are positive integers.
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