Need help on full structural formula

hi

It definitely isnt H7C4Br2CL as there is no bromine in the compound

Also, what you have given is the molecular formula, not the structural formula. For the structural formula you show how the atoms are bonded without showing the bonds themselves, e.g. butane's structual formula is CH3CH2CH2CH3 , not C4H10 as thats the molecular formula.

1,2-dichloro-3-fluorobutane has the following elements in it:

Chlorine
Fluroine
Carbon
Hydrogen

Use the prefrixes to work out how much of each element is in the compound. So Dichloro tells you theres 2 chlorine atoms, butane theres you there's 4 carbons etc. Once you've done this use the numbers to work out the position of the atoms, 1,2- dichloro tells you there's 1 Chlorine atom on the first 2 carbon atoms. Do this for the rest of the compound and you're done.

Remember its the structural formula, not the molecular formula.

hi thankyou chemistry is not my strong point. as im 50 and never did chemistry in 1978 at school and now going to university 1st year engineering but i have to get this module out of the road and its confusing at best.
So the structural formula is CLC2C2HF ? arghhh the notes on blackboard is so confusing - ppts

Ah I understand. Your answer is incorrect.

The answer is CH2ClCHClCHFCH3


Here's some points you will find helpful:

-Carbon atoms will always make 4 bonds.
- hydrogen atoms will bond only once.
- Carbons atoms will bond with each other to make the main body of the compound: C-C-C-C
- The carbon atoms will bind to hydrogen atoms so they meet the required 4 bond criteria. But they will also bind the other atoms if specified like the compound you are asking about. The important thing to remember is that the carbon atom must make 4 bonds.
- The numbers in the compound's name will tell you the position of that particular group/atom in the compound



So here's our compound :

1, 2- dichloro-3-florobutane

To make it easier break up the name into parts:


Butane= The main carbon chain has 4 carbon atoms.Remember each carbon atom will form 4 bonds


1- 2dichloro = Ok so there's 1 chlorine on the first carbon atom and another chlorine on the second carbon atom.
So for carbon 1 and 2 we have CCl-CCl but remember the carbons must make 4 bonds. The first carbon is bonded to the chlorine and the second carbon = 2bonds, so we add to hydrogen atoms to it to get 4 bonds : CH2Cl


The second carbon is bonded to the first carbon and a chlorine and ALSO the third carbon = 3 bonds. So we add a hydrogen to the second carbon to get 4 bonds : CH2Cl -CHCl - C

The second carbon is in bold and the dashes show that its bonded to 2 other carbons ( Don't put dashes in the answer, I;ve just done it to so its easier to understand)



3-fluorobutane = one fluorine atom on the third carbon = CF. But the 3rd carbon is also bonded to the second and fourth carbon = 3 bonds. So we add a hydrogen to get 4 bonds= CH2Cl -CHCl -CHF- C



The compound name does't specifiy anything about the fourth carbon but we know it must be bonded to the 3rd carbon atom so we add 3 hydrogen atoms to get 4 bonds: CH2Cl -CHCl -CHF- CH3

Now remove the dashes to get :

CH2ClCHClCHFCH3