4. a) Give a synonym for an unsaturated hydrocarbon.
b) Give the general formula (such as CxHy) for a hydrocarbon which has a double bond.
c) Give the general formula for a hydrocarbon which has a triple bond.
d) What is the difference between the “cis” and “trans” isomers?
a) Alkene
b) CxH2x
c) CxH2x-2
d) Cis-isomers have similar groups on the same side of the double bond, while trans-isomers have similar groups on opposite sides of the double bond.
a) A synonym for an unsaturated hydrocarbon is an alkene or olefin.
b) The general formula for a hydrocarbon with a double bond is CxH2x.
c) The general formula for a hydrocarbon with a triple bond is CxH2x-2.
d) The difference between "cis" and "trans" isomers lies in the spatial arrangement around a double bond. The term "cis" refers to molecules where the substituent groups are on the same side of the double bond, while "trans" refers to molecules where the substituent groups are on opposite sides of the double bond.
a) A synonym for an unsaturated hydrocarbon is an alkene.
b) The general formula for a hydrocarbon which has a double bond is CₙH₂ₙ-₂. This means that for each carbon in the molecule, there are two hydrogens attached, and the number of carbons (n) can vary. For example, ethene (C₂H₄) is a hydrocarbon with a double bond.
c) The general formula for a hydrocarbon which has a triple bond is CₙH₂ₙ-₄. This means that for each carbon in the molecule, there are two hydrogens attached, and the number of carbons (n) can vary. For example, ethyne (C₂H₂), also known as acetylene, is a hydrocarbon with a triple bond.
d) The terms "cis" and "trans" are used to describe the spatial arrangement of substituents around a double bond or a ring in a molecule. In a cis isomer, similar or identical groups are located on the same side of the double bond or the ring. In a trans isomer, these groups are located on opposite sides of the double bond or the ring.
To determine the "cis" and "trans" isomers, you need to examine the structure of the molecule. If there are two identical groups on the same side of the double bond or the ring, it is a cis isomer. If the two identical groups are on opposite sides, it is a trans isomer.
For example, in the case of cis-2-butene, the hydrogens that are attached to the carbons of the double bond are on the same side. In trans-2-butene, the hydrogens are on opposite sides.