VCE Chemistry Question Thread

[speedy]

What the hell is a 'radical' and do we have to know it?

[thushan]

H radical is fine; a radical is a species with an odd number of electrons.

As for butan-2-amine, 2-butanamine is actually also an older name, butan-2-amine is the actual correct IUPAC name.

@speedy - don't worry too much about it, it's just vocabulary. And yeah, you 'dot' the species to show that it has an odd number of electrons.

[speedy]

H radical is fine; a radical is a species with an odd number of electrons.

As for butan-2-amine, 2-butanamine is actually also an older name, butan-2-amine is the actual correct IUPAC name.

@speedy - don't worry too much about it, it's just vocabulary. And yeah, you 'dot' the species to show that it has an odd number of electrons.

Haha that was so quick... ty

[sparksfly]

When describing the non polar part of a molecule like ethanol, what do you call it? Would "the hydrocarbon part" do? Any better way in describing it?

Thanks 

[darklight]

I don't know if this thinking too much about it, but how come when forming a triglyceride the glycerol loses the 'H' and the fatty acid gives up its OH whereas in a 'normal' esterification reaction, the acid donates its acidic proton and the alcohol loses the 'OH' part?

[Robert123]

When describing the non polar part of a molecule like ethanol, what do you call it? Would "the hydrocarbon part" do? Any better way in describing it?

Thanks 

I believe it is  called an alkyl group (alkyl is a alkane group minus a hydrogen)

I don't know if this thinking too much about it, but how come when forming a triglyceride the glycerol loses the 'H' and the fatty acid gives up its OH whereas in a 'normal' esterification reaction, the acid donates its acidic proton and the alcohol loses the 'OH' part?

I believe for esterification, the acid actually does lose it's OH. I presume it would be similar to how an amide  linkage is formed where the acid clearly loses its OH.
The exact reason why though, I have no idea but I'm guessing it got to do with different bond strengths and energy level of molecules. That's far beyond the VCE level of the course
Hopefully that helps

[lzxnl]

I believe it is  called an alkyl group (alkyl is a alkane group minus a hydrogen)

I believe for esterification, the acid actually does lose it's OH. I presume it would be similar to how an amide  linkage is formed where the acid clearly loses its OH.
The exact reason why though, I have no idea but I'm guessing it got to do with different bond strengths and energy level of molecules. That's far beyond the VCE level of the course
Hopefully that helps

It's not to do with bond strengths. It's got to do with how the reaction works.
Essentially, in concentrated acid, the carboxylic acid group is protonated so that the OH becomes a OH2. Then, the OH2 is substituted for by the incoming alcohol.
Look up the mechanism; hard to describe using words. But it certainly doesn't have to do with bond strengths.

[Brunette15]

Can someone please help me with this part of the question? It's from the 2009 exam 2...

[speedy]

Can someone please help me with this part of the question? It's from the 2009 exam 2...

It's being recharged, so the reduction equation with the higher potential (top one) is forced backwards, it becomes the cathode. Thus the top equation is written in reverse and then you combine them.

[Zues]

just a few questions. Why is V1 the two volumes added, yet V2 is only the volume of the globe? i dont get this process


and also, could someone help with the attached MC, answer is C

[Bestie]

VCAA 2011 q5

I know the ans is A but can't it be B too?

[Valyria]

VCAA 2011 q5

I know the ans is A but can't it be B too?

Di-sulfide bridges aren't ionic, they are covalent. However, you are right for the first component as amide/covalent are interchangeable.

[allstar]

why does K value only change due to temp change?

What's enthalpy?

[Zues]

a thing that has been annoying me, as seen in attachment.
i thought Nitrogen is N? why do they say N2, is it nitrogen gas?

when writing chemical equations and they say hydrogen was produced etc.. do we write H or H2? why and when do we know when to do this

[allstar]

if it says produces hydrogen, then I think its saying H2 cause H can't exist by itself like that in the atmosphere, it will tend to bind with another H to form H2

Correct me if I'm wrong !