VCE Chemistry Question Thread

[RazzMeTazz]

Do we need to know about polyesters?

Are the monomers of polyesters always a dicarboxylic acid an a diol?

[Sidha]

Hi. I recently did the last sac for unit 3 Chem. I was doing decently before I did this sac. I have no yet recieved the result, but Im certain I did poorly. It was the aspirin sac, but it had everything in unit 3 on it. I was averaging 87%, and now I think my average will drop to high 70s. I think this will result in a C+ for unit 3 SACs coz the grade distributions are so high. It's so stupid. I really want to get a 35 for chemistry. If I manage an A+ for unit 4 sacs, and then an A on the exam, can I still get a 35 study score? So If I end up with C+,A+,A can I get a 35?

[RazzMeTazz]

Since aspirin contains an ester group, would it be an ester itself?

Also, would the reason for aspirin not being very soluble in water, because the molecule has larger non-polar regions, than it does polar regions?

Thanks

[Kel9901]

Hi. I recently did the last sac for unit 3 Chem. I was doing decently before I did this sac. I have no yet recieved the result, but Im certain I did poorly. It was the aspirin sac, but it had everything in unit 3 on it. I was averaging 87%, and now I think my average will drop to high 70s. I think this will result in a C+ for unit 3 SACs coz the grade distributions are so high. It's so stupid. I really want to get a 35 for chemistry. If I manage an A+ for unit 4 sacs, and then an A on the exam, can I still get a 35 study score? So If I end up with C+,A+,A can I get a 35?

of course you can get 35+!  possibly even 40+ if you get an A+ on the exam.

Since aspirin contains an ester group, would it be an ester itself?

Also, would the reason for aspirin not being very soluble in water, because the molecule has larger non-polar regions, than it does polar regions?

Thanks

yeah aspirin is an ester, it's made by combining a COOH group with an OH group, so yeah. (my knowledge is a little rusty so correct me if i'm wrong)

and yeah you're on the money there, it's because it's mostly non-polar

[RazzMeTazz]

When alkanes react with Cl2, a chloroalkane is formed.

In a similar fashion, can alkanes react with Br2, I2 and F2 to form other haloalkanes?
If yes, do these reactions also require the presence of either UV light or heat?
Thanks

[RazzMeTazz]

In the same way that the chlorine atom in chloroalkanes can be substituted for, with OH or NH2, can the same occur for the bromine, iodine and fluorine atoms in bromoalkanes, iodoalkanes and fluoroalkanes respectively?

[wunderkind52]

When alkanes react with Cl2, a chloroalkane is formed.

In a similar fashion, can alkanes react with Br2, I2 and F2 to form other haloalkanes?
If yes, do these reactions also require the presence of either UV light or heat?
Thanks

In the same way that the chlorine atom in chloroalkanes can be substituted for, with OH or NH2, can the same occur for the bromine, iodine and fluorine atoms in bromoalkanes, iodoalkanes and fluoroalkanes respectively?

Yes and Yes

[thushan]

When alkanes react with Cl2, a chloroalkane is formed.

In a similar fashion, can alkanes react with Br2, I2 and F2 to form other haloalkanes?
If yes, do these reactions also require the presence of either UV light or heat?
Thanks

Br2 and I2, but not F2. When it comes to the reactions you learn in VCE Chem, F2 always seems to be the exception (so don't worry about F2). In reality when you stick F2 to CH4, it will just rip all the H atoms off CH4 to form C and HF.

[lzxnl]

Since aspirin contains an ester group, would it be an ester itself?

Also, would the reason for aspirin not being very soluble in water, because the molecule has larger non-polar regions, than it does polar regions?

Thanks

Yes. It only has one acid group but it has a benzene ring and an ester group, neither of which are particularly polar.

Br2 and I2, but not F2. When it comes to the reactions you learn in VCE Chem, F2 always seems to be the exception (so don't worry about F2). In reality when you stick F2 to CH4, it will just rip all the H atoms off CH4 to form C and HF.

I think it'd depend on how much you add too. I can envisage the formation of CF4.

[warya]

Could someone help me with this question and if I have the ones I answered right

[Sundal]

Are we required to know about dehydration reactions involving alkanols for the VCE course?

(e.g. "ethanol vapour is passed over heated aluminium oxide, water is eliminated from the alcohol an ethene gas is produced. A dehydrating agent such as concentrated H2SO4 is required." - TSFX notes.)

Do we also need to know about alkanols being able to act as acids and bases?

[Sundal]

Should benzene be drawn with double bonds between the C atoms or not?

Because I seem to have seen both!

[Sidha]

of course you can get 35+!  possibly even 40+ if you get an A+ on the exam.

No I think a 40 is now impossible. I was originally aiming for a 40, but I would be thrilled with a 35. My goal is to achieve a 90+ ATAR.

[thushan]

Should benzene be drawn with double bonds between the C atoms or not?

Because I seem to have seen both!

Either is fine.

[warya]

Could someone explain the saponification test for my sac tomorrow we will try to make soap out of oleic, olive and sunflower oil