Question

why is 6-decene not possible

Answer 1

start by drawing decane (10 saturated carbon atoms in a chain)

Answer 2

then put a double-bond on carbon 6

Answer 3

from the structure, determine it's proper name under iupac rules (the lowest number must be given to the double bond)

Answer 4

what is the lowest number?

Answer 5

so carbon 1 is the lowest number?

Answer 6

sorry, i still don't get it

Answer 7

you can start numbering from the left side or the right side

which direction gives the double bond the lowest number?

Answer 8

but how would you know by just knowing the formula?

Answer 9

how would I know what?

Answer 10

the direction?

Answer 11

whichever direction gives the alkene bond the lowest number is the correct direction

Answer 12

try both directions.

start numbering the carbons from the left
then try numbering the carbons from the right

which one gives you the lowest number for the alkene bond?

Answer 13

what do i do next?

Answer 14

\(\color{#0cbb34}{\text{Originally Posted by}}\) @Vocaloid
then put a double-bond on carbon 6
\(\color{#0cbb34}{\text{End of Quote}}\)

Answer 15

that's carbon 5

Answer 16

good

now try numbering the compound from the left
then try from the right

then see which direction gives the lowest number for the double bond

Answer 17

good

so the compound's actual name is 4-decene

Answer 18

(6-decene is not a proper name under iupac)

Answer 19

some of the website said is 2-decene?

Answer 20

no idea how they got 2-decene

Answer 21

the only possibility is 4 ?

Answer 22

yes

Answer 23

what does it mean "dec-6-ene"

Answer 24

dec-6-ene is just another way to write 6-decene

Answer 25

sometimes the double-bond locant is written after the latin prefix

Answer 26

so 6-decene is not possible

Answer 27

no it is not possible

Answer 28

but why do i draw the double in the #6 carbon

Answer 29

*bond

Answer 30

the original name is incorrect but we can use it to figure out the correct name

Answer 31

6-decene means a double bond on the 6th carbon

Answer 32

(from the wrong direction)

Answer 33

the right location is at #4 carbon?

Answer 34

it's the 6th from the wrong direction and the 4th from the right direction

Answer 35

???

Answer 36

let me try to explain

Answer 37

ok

Answer 38

thx

Answer 39

normally we would give iupac names to give the double bond the lowest number

Answer 40

imagine a bad chemist found a compound, named it from the wrong direction, and told you there was a double bond on carbon 6

Answer 41

giving you the name 6-decene

Answer 42

now, a good chemist will use that name to draw the compound. he draws it, and realizes that he needs to number it from the other end to give the proper iupac name

Answer 43

making the real name 4-decene

Answer 44

the "6th carbon" is part of the bad chemist's misinformation

Answer 45

but we can use that misinformation to get the real name

Answer 46

ok

Answer 47

got it now

Answer 48

can i ask you another question?

Answer 49

sure

Answer 50

why butene have 2 ways to draw?

Answer 51

that's ok

Answer 52

the question is how many ways can you write butene?

Answer 53

and the answer is 1,2-butene but idk why is that answer

Answer 54

oh I think they just want these two structures

Answer 55

1-butene: H3C-CH2-CH=CH2

2-butene: H3C-CH=CH-CH3

both are considered butene but one has the double bond shifted over to the 2-carbon position

Answer 56

yeah, but how would you know that there are 2 structures?

Answer 57

but- implies 4 carbons
-ene implies one double bond (otherwise it would be butadiene)

Answer 58

1-butene and 2-butene are both classified as butene

Answer 59

so one of them has the double bond in the end and the other one has the double bond in the middle

Answer 60

you would just have to use some intuition + sketching out possible structures

Answer 61

how come it can't be 3-butene?

Answer 62

lowest number rule

Answer 63

it have to start from the left

Answer 64

no it doesn't

it starts from whichever direction gives the lowest number

Answer 65

1-butene: H3C-CH2-CH=CH2

2-butene: H3C-CH=CH-CH3

"3-butene:" H3C=CH-CH-CH3

notice how "3-butene" is just 1-butene rotated around

Answer 66

yes

Answer 67

omg, i finally got it

Answer 68

since 1-butene has a lower number, then "3-butene" gets renamed as 1-butene

Answer 69

good

Answer 70

thank you so much

Answer 71

Can I ask for help in the future?

Answer 72

sure

Answer 73

thx, good night!!!!!

Answer 74

Moved to Chemistry