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Hi all, please see this major site announcement: https://www.boards.ie/discussion/2058427594/boards-ie-2026
***2013 LC Chemistry Before/After***
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Acciaccatura wrote: »2-methylpropanal - CH3CH(CH3)HC=O
2-butanone - CH3C=OC2H5
Can't think of a third one
butanal itself is also an isomer CH3CH3CHO0 -
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KildareKing wrote: »butanal itself is also an isomer CH3CH3CHO
Oh yeah... :rolleyes: Thanks!
Silly mistakes like that will kill me tomorrow
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Acciaccatura wrote: »2-methylpropanal - CH3CH(CH3)HC=O
2-butanone - CH3C=OC2H5
Can't think of a third one
Butanal's isomers are not on our course.0 -
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My dream paper/section A predictions include:
Q1- Winkler method or iodine/thiosulfate titration. If crystallization comes up I dunno what I'll do.
Q.2- Ethanoic acid/Ethanal or ethyne, it usually comes up after ethene, but it's not much to go by. Or soap.
Q.3- Rate of reaction exp. or determining heat of reaction. Hopefully
Usual stuff on Q.4, 5 and 6
A full question on water, full question on equilibrium and a full q. on gases between 7,8 and 9
10 and 11- Radioactivity, instrumentation, industrial chemistry, redox stuff is due here too, I forget the rest I'd thought of.0 -
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Oh yeah ! I mixed between benzoic acid and water !
Please God let it be winkler
By the way the answer for WHY C.Acids are acid is this :
The electrons are drawn from the O in the OH group towards the carbonyl group " inductive effect" allows the H of the hydroxyl group to be donated.0 -
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Oh yeah ! I mixed between benzoic acid and water !
Please God let it be winkler
By the way the answer for WHY C.Acids are acid is this :
The electrons are drawn from the O in the OH group towards the carbonyl group " inductive effect" allows the H of the hydroxyl group to be donated.
That's only one of them
also the stability of the carboxylate ion OC=O0 -
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I AM SO SLEEP DEPRIVED UGH. I've spent all day worrying about how i did in my physics i've done nothing for this yet I don't even know where to start... somebody ask me a question please!
Sure haha, I feel the same way. How did it go for you?
these were on my mock in Q.4
1. Define relative atomic mass
2. Distinguish between sigma and pi covalent bonding
3. What happens during secondary sewage treatment?
4. What are the possible shapes for molecules of general formula AB3
5. What is meant by homogenous catalysis?
6. What are mercaptans?
7. Write the conjugate acid and conjugate base of H2PO4-
8. How does nitrogen fixation occur in nature
or
8. Give an example of (i) An ionic crystal and (ii) a covalent macromolecular crystal
Your turn haha
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Sure haha, I feel the same way. How did it go for you?
these were on my mock in Q.4
1. Define relative atomic mass
2. Distinguish between sigma and pi covalent bonding
3. What happens during secondary sewage treatment?
4. What are the possible shapes for molecules of general formula AB3
5. What is meant by homogenous catalysis?
6. What are mercaptans?
7. Write the conjugate acid and conjugate base of H2PO4-
8. How does nitrogen fixation occur in nature
or
8. Give an example of (i) An ionic crystal and (ii) a covalent macromolecular crystal
Your turn haha
not gonna write all these out cause i'm too lazy :P think i can do most of these but what do you say for 2 and the first one in 8?
i'll give you a few :
1 - define electronegativity
2 - why is sulphuric acid added when making up iron tablets?
3 - what is Hess's law?
4 - what colour is methyl orange in a base?
5 - why do ionisation enegries decrease down the group?0 -
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2. Sigma bonding is the "head on overlapping" of orbitals 2 's' orbitals, an 's' and a 'p' and 2 'p' orbitals. Can't really draw them out here, gimme a min and ill take a pic haha. Pi bonding is the weaker of the two due to less overlapping of orbitals. Pi is the "side on overlap" of two 'p' orbitals
8. The root nodules of legumes such as clover or industrial processes or the easiest one to remember is lightning.
Not sure the exact wording of Hess' law. Something like "the heat change in a reaction is independent of the path followed and only depends on the initial and final stages"
4. Methyl orange is yellow in a base isn't it?
5. Screening effect ^^ The others are all good
Oh yeah I remember Do you think it would be okay leaving out all of electrolysis and the atomic structure and the option? 0 -
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Even if you know the basics of each you should be fine. The option question should be very short anyway so that you're grand leaving.Oh yeah I remember Do you think it would be okay leaving out all of electrolysis and the atomic structure and the option?
What about the Iron(II) question? Why sulfuric acid? Prevent oxidation to Iron(III)?:P0 -
Even if you know the basics of each you should be fine. The option question should be very short anyway so that you're grand leaving.
What about the Iron(II) question? Why sulfuric acid? Prevent oxidation to Iron(III)?:P
Oh sorry, yep that's it exactly! and then you add more later to ensure a MnO4- is fully reduced to Mn2+ 0 -
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Same here. I think i'm getting sick cause I keep getting really warm and dizzy and in the exam today i kept zoning out and forgetting where i was... I'm not doing anything for spanish either, I'll just wing it and fail the listening as per usual
They got such a nice paper last year tho 0 -
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MarieCurie22 wrote: »They got such a nice paper last year tho
true wasn't expecting Boyle's law to come up 2 years in a row or the I/V Graphs tbh. Nonetheless welcome though!:D 0
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