U3-2-1 - Geometric Isomers Flashcards
1
Q
When can geometric isomers occur?
A
When there is a lack of free rotation around a C to C bond, e.g. C=C or ring structure.
2
Q
Is this isomer cis or trans?
A
Cis
both CH3 groups on the same side of C=C
3
Q
Is this isomer cis or trans?
A
Trans
both CH3 groups on opposite sides of C=C
4
Q
Why is this isomer cis?
A
Both substituents (CH3) on the same side of the C=C bond.
5
Q
Why is this isomer trans?
A
Both substituents (CH3) on opposite sides of the C=C bond.
6
Q
Why does propene not have geometric isomers?
A
Propene has two hydrogens attached to the first carbon of C=C.
7
Q
Will cis or trans isomers have the higher melting point?
A
Trans
8
Q
Why do trans isomers have higher melting points?
A
Closer packing due to their shape allows for stronger IMFs.
