How Pedantic are the markers with fructose

[maveric31]

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If your familar with fructose.. when you look at the 2 carbon atoms that both connect with the oxygen atom, one atoms connects with an OH and HOCH2 and the other with a H and CH2OH.
My question is what is the difference between HOCH2 and CH2OH?, the past paper anwsers and my text book both state it this way, but dont say why.

do the markers mind if we write them both out as CH2OH, or does it have to be HOCH2 and CH2OH and if so could somone plz explain why they are like this?
thank you

[moonpie91]

sorry, i dont have answer for ur question

but do we need to know and draw structual formulas for carbohydrates?

i have never come across any questions asking that specifically about structual formula of fructose or any carbohydrates.

[The Nomad]

Well I don't do this option, but I'm pretty sure it's because there's a bond between the 2 carbon atoms, and no bond between the carbon and hydrogen (in the hydroxyle group). Writing it that way just shows the marker you know which atoms are bonded together.

[maveric31]

"Sucrose is a disachharide. write an equation using structural formulae for the reaction of glucose and fructose to form sucrose"
.....
and as we know sucrose is formed from alpha glucose and beta fructose..

[brenton1987]

Originally Posted by maveric31

If your familar with fructose.. when you look at the 2 carbon atoms that both connect with the oxygen atom, one atoms connects with an OH and HOCH2 and the other with a H and CH2OH.
My question is what is the difference between HOCH2 and CH2OH?, the past paper anwsers and my text book both state it this way, but dont say why.

There is really no difference but it shows the attachment of the atoms.

Originally Posted by maveric31

do the markers mind if we write them both out as CH2OH, or does it have to be HOCH2 and CH2OH and if so could somone plz explain why they are like this?

You would have to have them written to show the correct bonding of atoms. That means HOCH₂ on the left and CH₂OH on the right. Otherwise the bonding is wrong so the structure isnt fructose.

[moonpie91]

Originally Posted by maveric31

"Sucrose is a disachharide. write an equation using structural formulae for the reaction of glucose and fructose to form sucrose"
.....
and as we know sucrose is formed from alpha glucose and beta fructose..

hey maveric31 is that question u wrote from an actual chemistry paper?

coz i dont see any dotpoint about structural formula of sucrose in the syllabus

[maveric31]

i've found it in the success one HSC chemistry section for just forensic chemistry, i havent found it in any HSC past exams, but i was told by my teacher that we should know the structure plus he put it in my trial.. i think he is or was a chem marker.. but im not 100 percent sure if we should know it or not... im only going by what he told me.

[we0426]

Originally Posted by maveric31

i've found it in the success one HSC chemistry section for just forensic chemistry, i havent found it in any HSC past exams, but i was told by my teacher that we should know the structure plus he put it in my trial.. i think he is or was a chem marker.. but im not 100 percent sure if we should know it or not... im only going by what he told me.

hey u should write like CH2OH.. if u look at how we write ethanol..C2H5OH..U SEE WHAT I MEAN..

THIS OPTION IS COOL BUT SO MUCH TO REMEMBER FOR PRACS GOD..ANY WAYS MATEE MY TEACHER WHO WAS A MACQUARI UNI LECTURERR TOLD US TO WRITE LIKE THAT.. i hope my life story helped u in any shape or form...

[brenton1987]

Originally Posted by we0426

hey u should write like CH2OH.. if u look at how we write ethanol..C2H5OH..U SEE WHAT I MEAN..

They are not equivalent ways of writing formulae.

To make your point it should have been ethanol as CH₃CH₂OH because it shows how the atoms are attached to eachother.

[we0426]

Originally Posted by brenton1987

They are not equivalent ways of writing formulae.

To make your point it should have been ethanol as CH₃CH₂OH because it shows how the atoms are attached to eachother.

nah i can bet u that they way u write is accepted but its not the right way..i swear to god i lost 4 marks on a 8 marker coz i wrote ethanol like the way u wrote it..if u see fermentation reaction and esterfication u would no what i mean....BUT ITS UP TO U MY FRIEND I AINT SOME ONE TO CHANGE SOME ONES MINd FRANKLY ITS JUST MY 2 CENTS worth....so its all up to u....