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# Difference between structural and displayed formula? watch

1. As the title says..

Difference between structural and displayed formula?

Also, can anyone tell me how to draw 2,2-dimethylbromopropane

Thanks
2. Draw Propane (H3CC(H2)CH3), then remove both of the hydrogens on Carbon 2, and add two Methyl groups, CH3, to the Carbon.

Can't draw the 'Bromo-' part as we don't know which Carbon the Bromine atom is on.

EDIT: A structural formula shows how the various atoms are bonded. There are various ways of drawing this and you will need to be familiar with all of them. A displayed formula is a type of structural formula and shows all the bonds in the molecule as individual lines, where each line represents a pair of shared electrons.
3. To draw a molecule, find the bit where it tells you the longest chain, in this case propane, then draw the chain with only C-C bonds.
Then add the other stuff onto the chain, so you would add 2 methyl groups onto the second carbon.
You then know that because the 2nd carbon has 4 bonds that you need to put the bromine on one of the end carbons. In this case it doesn't matter which because it would be the same no matter which it's on.
From here you just need to add hydrogens to give every carbon the right number of bonds.
4. Strangely enough, I thought displayed = the one you've given and structural = full bonds drawn out. However, this thread disagrees:

http://www.thestudentroom.co.uk/show....php?t=1146773

With regards to the position of bromine, if there's no number it'd be safe to assume it's position one. So 2,2 dimethyl-1-bromopropane.
5. Structural shows where everything is and lists all the groups but without bonds eg propane, CH3CH2CH3
but displayed shows all the letters and all the bonds between them
6. (Original post by thegodofgod)
Draw Propane (H3CC(H2)CH3), then remove both of the hydrogens on Carbon 2, and add two Methyl groups, CH3, to the Carbon.

Can't draw the 'Bromo-' part as we don't know which Carbon the Bromine atom is on.

EDIT: A structural formula shows how the various atoms are bonded. There are various ways of drawing this and you will need to be familiar with all of them. A displayed formula is a type of structural formula and shows all the bonds in the molecule as individual lines, where each line represents a pair of shared electrons.
In a exam style question I am doing, it says the two structural isomers are given below. Then below it theres one like this CH3CH2CH2CH2Br and then the actual thing draw out... how can they both be structural isomers?
7. (Original post by xXxiKillxXx)
In a exam style question I am doing, it says the two structural isomers are given below. Then below it theres one like this CH3CH2CH2CH2Br and then the actual thing draw out... how can they both be structural isomers?
They're both structural isomers as they both contain the same number of atom of each element, but are arranged differently in space: 1-bromo-2,2-dimethylpropane is not the same as 1-bromopentane.
8. (Original post by thegodofgod)
Draw Propane (H3CC(H2)CH3), then remove both of the hydrogens on Carbon 2, and add two Methyl groups, CH3, to the Carbon.

Can't draw the 'Bromo-' part as we don't know which Carbon the Bromine atom is on.

EDIT: A structural formula shows how the various atoms are bonded. There are various ways of drawing this and you will need to be familiar with all of them. A displayed formula is a type of structural formula and shows all the bonds in the molecule as individual lines, where each line represents a pair of shared electrons.
If in doubt, quote chemguide.

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