Carbon and its compounds Flashcards
(29 cards)
Allotropy
The property possessed by certain elements to exist in two or more distinct forms that are chemically identical but have different physical properties due to the difference in arrangement of atoms
Combined states of carbon
· Solid : Animal and plant products – cellulose, carbohydrates, fats , proteins etc.
As mineral salts in the form of carbonates- lime, marble, chalk (CaCO3), Magnesite ( MgCO3) , Dolomite ( MgCO3. CaCO3), Calamine ( ZnCO3)
· Liquid : Petroleum and vegetable oils
· Gaseous : Air contains 0.03% by volume of CO2, natural gas, marsh gas, petroleum gas, coal gas
properties of diamond
Hardest substance known to man
brittle (not malleable)
insulator (non-conductor)
insoluble in water
very high melting point
properties of graphite
Brittle
Soft and slippery
Electrical conductor
Insoluble in water.
Very high melting point
Covalent bond
A chemical bond formed between two non metallic elements by mutual sharing of one or more electron pairs, is called a covalent bond
Covalent compounds
The chemical compound formed by mutual sharing of electron pairs between two or more different kind of atoms, is called a covalent compound.
Catenation
It has a unique property to form bonds with other carbon atoms, so as to form long straight, chains, branched chains and closed rings, giving rise to large number of molecules. The carbon atoms link with each other to form single, double and triple bond. This property of carbon to link with other carbon atoms with single, double and triple covalent bonds so as to form large number of compounds is called catenation.
Organic chemistry:
The branch of chemistry dealing with carbon compounds, other than CO, CO2, carbonates and hydrogen carbonates is called Organic chemistry
Organic compounds
The compounds of carbon, other than oxides, carbonates and hydro carbonates are called organic compounds
HYDROCARBON
Organic compounds of carbon and hydrogen are called as hydrocarbons.
Saturated hydrocarbons
The compounds of carbon in which each valency of carbon is satisfied by a single covalent bond are called Saturated Carbon Compounds.
Unsaturated hydrocarbons
The compounds of carbon in which the valency between two carbon atoms in a carbon chain is satisfied by a double or triple covalent bond are called Unsaturated Carbon Compounds.
Properties of homologous series
· All members of a homologous series can be represented by a general formula, for
· Each member of the homologous series differs from the next member by a –CH2 group.
· Each member of the homologous series differs from the next member in molecular mass by 14 amu.
· Due to the change in molecular mass, physical properties of homologues differ from other homologues. homologues in a particular series have graded physical properties.
· All homologues have same chemical properties.
· All homologues can be prepared by the same general method of preparation
ISOMERISM
Isomers are compounds having the same molecular formula but different structural formula due to the difference in the arrangements of carbon atoms. They have different physical and chemical properties. The phenomenon exhibited is called isomerism.
Characteristics of isomers
· same molecular formula
· different structural formula
· Different arrangement of carbon atoms.
· Different physical and chemical properties.
Functional group
The functional groups are specific groups of atoms within an organic compound that are responsible for its characteristic chemical properties.
heteroatom
In a hydrocarbon chain, one or more hydrogen can be replaced by atoms of other elements, such that the valency of carbon remains satisfied. In such compounds, the element replacing hydrogen is referred to as a heteroatom.
A mixture of acetylene (ethyne) and air cannot be used for welding why?
A mixture of acetylene (ethyne) and air cannot be used for welding because of the low percentage of oxygen in the air; it leads to incomplete combustion producing a yellow sooty flame which is not enough to melt metals.
Substitution reaction
The reaction in which one or more hydrogen atoms of a hydrocarbon are replaced by other atoms like chlorine, bromine, fluorine is called substitution.
Addition reaction
The reaction in which an unsaturated hydrocarbon combines with another substance to give a single product is called an addition reaction.
Bromination :
The addition of bromine to an unsaturated hydrocarbon to obtain a saturated hydrocarbon is called bromination.
The physical properties of acetic acid are
· It is a colourless liquid
· It is sour in taste
· It smells like vinegar
· Its boiling point is 118°C
· Its melting point is 17°C , hence it often freezes in winters ,to form ice – like flakes resembling glacier therefore, it is also known as glacial acetic acid.
· It is miscible with water in all proportions.
Esters
Esters are usually volatile liquids having a sweet fruity smell. They are used for making artificial perfumes and soaps. They are also used as a flavouring agent in making artificial flavours and essences used in ice creams, cold drinks sweets etc.
Uses of acetic acid
- Dilute acetic acid (vinegar) is used as a food preservative in pickles , sauces etc and as an appetizer in salads etc.
- It is also used to make cellulose acetate which is an important artificial fibre.
- It is also used in the coagulation rubber from the latex.(sap of rubber plant )
- It is also used in the preparation of dyes, paints, plastics.
- It is also used in the manufacture of acetone and esters
