Alkenes are defined as either branched or unbranched hydrocarbons that possess at least one carbon–carbon double bond (CC) and have a general formula of
CnH2n [1]
.
Do alkenes have same general formula?
Alkenes and Cycloalkanes have the same general formula,
C
n
H
2n
. Therefore, the general formula does not identify the structure as an alkene nor an cycloalkane. To further become problematic there are alkenes which contain more than one double bond. Those with two double bonds have the formula, C
n
H
2n – 2
.
Which is an alkene?
In chemistry, an alkene is
a hydrocarbon containing a carbon–carbon double bond
. Alkene is often used as synonym of olefin, that is, any hydrocarbon containing one or more double bonds. Two general types of monoalkenes are distinguished: terminal and internal. Also called α-olefins, terminal alkenes are more useful.
What is structure of alkenes?
Alkenes are a class of
hydrocarbons
(i.e., containing only carbon and hydrogen). They are unsaturated compounds with at least one carbon-to-carbon double bond. The double bond makes alkenes more reactive than alkanes.
What are alkenes examples?
| IUPAC Name Molecular Formula Condensed Structural Formula | ethene C 2 H 4 CH 2 =CH 2 | propene C 3 H 6 CH 2 =CHCH 3 | 1-butene C 4 H 8 CH 2 =CHCH 2 CH 3 | 1-pentene C 5 H 10 CH 2 =CH(CH 2 ) 2 CH 3 |
|---|
Why is 3 butene not a proper name?
Locate the double bond by the number of its first carbon. In this compound, the double bond begins at carbon #1, so the full name becomes: 1-butene. Note the INcorrect numbering in the second structure.
There is no such compound as 3-butene
.
What are the first 10 alkenes?
- Ethene (C
2
H
4
) - Propene (C
3
H
6
) - Butene (C
4
H
8
) - Pentene (C
5
H
10
) - Hexene (C
6
H
12
) - Heptene (C
7
H
14
) - Octene (C
8
H
16
) - Nonene (C
9
H
18
)
What is the general formula of alcohol?
The molecular formula of ethanol is
C2H6O
, indicating that ethanol contains two carbons and an oxygen. However, the structural formula of ethanol, C2H5OH, provides a little more detail, and indicates that there is an hydroxyl group (-OH) at the end of the 2-carbon chain (Figure 1.1).
What is the general formula of alkyl?
An acyclic alkyl has the general formula of
C
n
H
2n + 1
. A cycloalkyl is derived from a cycloalkane by removal of a hydrogen atom from a ring and has the general formula C
n
H
2n – 1
. Typically an alkyl is a part of a larger molecule. In structural formula, the symbol R is used to designate a generic (unspecified) alkyl group.
What is the structure of Propyne?
Propyne (methylacetylene) is an alkyne with the chemical formula
CH
3
C≡CH
. It is a component of MAPD gas—along with its isomer propadiene (allene), which was commonly used in gas welding. Unlike acetylene, propyne can be safely condensed.
What do all alkenes have in common?
While the physical state of alkenes varies depending on the number of carbon atoms, what alkenes have in common is that
they are both insoluble in and less dense than water.
What is the main use of alkenes?
In manufacturing, alkenes find many different applications. They are used in the
synthesis of alcohols, plastics, lacquers, detergents, and fuels as starting materials
. For the chemical industry, the most important alkenes are ethene, propene, and 1,3-butadiene.
How do we name alkenes?
Higher alkenes and alkynes are named by
counting the number of carbons in the longest continuous chain
that includes the double or triple bond and appending an -ene (alkene) or -yne (alkyne) suffix to the stem name of the unbranched alkane having that number of carbons.
