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Q19 Bauklkham Hills. Module 7 addition polymerization (1 Viewer)

carrotsss

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All gir- I mean all chem trial papers are the same
yeah pretty much

i haven’t done ruse papers yet but all good papers I have done feel pretty much identical like there aren’t really many ways to make papers harder other than more long response qs where you lose 1 or 2 marks
 

Luukas.2

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Extending on @nsw..wollongong's post:

There are two isomeric pentanone's:
  • 2-pentanone, CH3-CO-CH2-CH2-CH3, in which there are 5 x C environments and 4 x H environments, because the molecule is not symmetrical about the carbonyl group (-CO-), and
  • 3-pentanone, CH3-CH2-CO-CH2-CH3, in which there are 3 x C environments and 2 x H environments, because the molecule is symmetrical about the carbonyl group (-CO-).
Similarly, 5-nonanone will have only 5 x C environments and 4 x H environments, whereas 2-nonanone, 3-nonanone, and 4-nonanone will all have 9 x C environments and 8 x H environments. It does not matter how far away any differences might be, each environment that is not absolutely identical to another will count as a separate environment.
 

Interdice

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How can we tell if it's an aldehyde or ketone?
 

Luukas.2

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It's a ketone. Aldehydes have medium to strong bands (usually two of them) below the regular C-H band for the C-H of the terminal -CHO - somewhere like 2700 - 2800 cm-1.

The IR spectrum for propanal can be seen at https: / / webbook.nist.gov/cgi/cbook.cgi?Spec=C123386&Index=0&Type=IR&Large=on&SVG=on (take out the spaces around the slashes) - you'll see that the extra aldehydic C-H bands are prominent.
 

Interdice

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It's a ketone. Aldehydes have medium to strong bands (usually two of them) below the regular C-H band for the C-H of the terminal -CHO - somewhere like 2700 - 2800 cm-1.

The IR spectrum for propanal can be seen at https: / / webbook.nist.gov/cgi/cbook.cgi?Spec=C123386&Index=0&Type=IR&Large=on&SVG=on (take out the spaces around the slashes) - you'll see that the extra aldehydic C-H bands are prominent.
Thanks. I read that section like 5 times on the pearson textbook, and I swear that isn't there
 

Luukas.2

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Most texts / teachers / tutors don't point out that the C-H bands can be informative. The bands at lower wavenumber for an aldehyde are the most obvious, but signals above the usual range can also help, reflecting H-C=C, H-C(aromatic, like a benzene ring), and H-C(alkyne). All are sharp and completely unlike an N-H or O-H band.
 

Interdice

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Where to get Proton NMR questions?

There are barley any resources on them. Past trial papers don't have proton NMR usually. Where can I get questions.

I also don't want to start HSC exam papers yet.
 

Interdice

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1696040469279.png

Are pressure questoins in the scope of this course? Never seen them before
 

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