HSC Chemistry Exam Solutions / Thoughts (5 Viewers)

[Arrowshaft]

Just a piece of advice with those society questions. Technically it is a society, economics etc question BUT what the examiners are actually looking for there is not your understanding of like saying things are renewable or making blanket statements. They are more looking for are you able to link the chemistry you have learnt to a society, environmental or economics issue.

For instance if someone just said ethanol is renewable I wouldn't be inclined to give that a good mark. There's no link to the chemistry you have learnt. A better answer would be ethanol is renewable when derived from plants such as maze or sugar cane. This provides a glucose source which can be used in fermentation (INSERT CHEMICAL EQUATION)

That there is a way better way to justify something

Another example, if I am talking about an advantage to the economy of fossil fuels. Lets say I say something like fossil fuels are used in a variety of places that improve human life such as home appliances, fuel sources, agriculture, stoves and heating. You can make your answer better and link it to the chemistry, by saying what the specific hydrocarbons are used in each application. So for example methane in stoves (EQUATION), fuel sources use octane normally (EQUATION), agriculture uses diesel (EQUATION), coal for electricity (EQUATION)

One last example, ethanol has a disadvantage to economics in terms of cars as water gets dissolved in it which will corrode engines. Here is a perfect opportunity for you to discuss your knowledge on intermolecular forces. So add in your answer, ethanol is a polar molecule and has dipole-dipole interactions as well as hydrogen bonding which allows water to dissolve in it (CAN EVEN STICK IN THE DIAGRAM HERE SHOWING THE HYDROGEN BOND BETWEEN ETHANOL AND WATER). This is a problem for a fuel source because water is corrosive to metals in the engine lining (EQUATION here for rust if you know it)

So make sure you don't just write a million words in those questions try to attach chemical equations and chemistry principles everywhere

This is very helpful, thank you so much

 

[jazz519]

Very helpful. Thanks

This is very helpful, thank you so much

No worries

 

[AHafza]

I don’t think it’ll be Haber since they already asked it, maybe Contact process and asking you to discuss the effect of each reaction

I don’t think they can go specific on either processes unless it’s tied to another module

 

[AHafza]

Because giving a question purely about the process isn’t applicable for all as we all studies different chemical processes and the syllabus doesn’t specify which process to study

 

[Arrowshaft]

Because giving a question purely about the process isn’t applicable for all as we all studies different chemical processes and the syllabus doesn’t specify which process to study

I meant that they’d give us the information about the processes and ask us to analyse them

 

[AHafza]

I meant that they’d give us the information about the processes and ask us to analyse them

Oh yh... fair enough

 

[AHafza]

Good luck guys

 

[Arrowshaft]

Good luck guys

Thanks mate, yeah gl everyone!

 

[jazz519]

First off congratulations on finishing your year 12 chemistry exam. For a lot of you probably your last exam so also congratulations on finishing your HSC. Make sure to take some time now to enjoy yourself and try not to worry too much about HSC results yet. If you still have exams left, it's almost over so keep up the intensity and work

How'd the exam go guys? What were the long responses on? Was there a lot of calculations or a lot of written questions?

Also, if anyone by the off chance has the paper please send it through to me and I'll write up solutions for you guys

 

[Arrowshaft]

I am really happy with how it went! The two 7 markers were pretty much analytical and not theory based. One was where you had to plot the absorbance vs concentration for AAS and the other was a reaction pathway which was very fun. Not really many theory questions, a lot of calculations; not even a single extended response question on polymers which I was surprised about. There was a question like we predicted involving 4 spectra, H NMR, C NMR, Mass spec, IR spec. Which was also pretty fun, they asked you to identify the compound and draw it’s structural formula. Multiple choice was also surprisingly easy, a lot easier than sample questions. All in all, I’m pretty happy with it! Hopefully, it all went well for everyone else as well, and if not it’s not the end of the world

 

[jazz519]

I am really happy with how it went! The two 7 markers were pretty much analytical and not theory based. One was where you had to plot the absorbable vs concentration for AAS and the other was a reaction pathway which was very fun. Not really many theory questions, a lot of calculations; not even a single extended response question on polymers which I was surprised about. There was a question like we predicted involving 4 spectra, H NMR, C NMR, Mass spec, IR spec. Which was also pretty fun, they asked you to identify the compound and draw it’s structural formula. Multiple choice was also surprisingly easy, a lot easier than sample questions. All in all, I’m pretty happy with it! Hopefully, it all went well for everyone else as well, and if not it’s not the end of the world

Yep lol knew they were gonna put the spectrums one and reaction pathways haha. But that's great to hear congrats on doing well

 

[Hithcock]

Same here, a very manageable paper. There was one question where we had to compare the effect of enthalpy and entropy on the solubility of two compounds that threw me off, but other than that, it was pretty decent!

 

[jazz519]

Same here, a very manageable paper. There was one question where we had to compare the effect of enthalpy and entropy on the solubility of two compounds that threw me off, but other than that, it was pretty decent!

ohhh just off what you told me there that's probably got something to do with K constant for enthalpy bit. Remember that Ksp is affected by temperature

 

[Arrowshaft]

ohhh just off what you told me there that's probably got something to do with K constant for enthalpy bit. Remember that Ksp is affected by temperature

Actually no, they provided us with data on delta H, delta S and T delta S, and Gibbs free energy. THEY already calculated everything for us, it was very weird

 

[jazz519]

Actually no, they provided us with data on delta H, delta S and T delta S, and Gibbs free energy. THEY already calculated everything for us, it was very weird

damn interested to see that question when I get a chance to see the paper

 

[AHafza]

For the 7marker was did u guys calculate that it was effective for cu but ineffective for pb?

 

[Hithcock]

For the 7marker was did u guys calculate that it was effective for cu but ineffective for pb?

Yep

 

[Arrowshaft]

For the 7marker was did u guys calculate that it was effective for cu but ineffective for pb?

Wait did you get effective for cu? I got 1.26 something for Cu...

 

[vedantpatel]

what did u guys say for enthaply qn?? and why was it negative?

 

[AHafza]

Wait did you get effective for cu? I got 1.26 something for Cu...

I guess one of us is wrong... in the case that u have the right process but Ofc get the answer and conclusion wrong for cu, it’s only a 2 mark deduction? Right?