Chemistry Predictions/Thoughts (4 Viewers)

[user1207]

what is the probability that they'll ask us a long Mod 8 anion/cation testing question this year..... I do not think I will be good at gambling but I cannot absorb the solubility table for the life of me.

looking at the ksp on the data sheet can help with what's insoluble and what ppt's

 

[pancake15]

Do we, I thought they usually give the condensation polymers and then tell you to show the monomer, but you have to remember the addition polymers for sure.

syllabus mentions "nylon and polyesters" by name as an example in the same way they do for addition polymers, it specifies MODEL and compare structure, properties and uses of condensation polymers so bare minimum id say remember what types of monomers can be used + the linking functional group

again, better safe than sorry though

 

[randomuser246]

How do you answer questions about the effect of enthalpy and entropy on the reactions

 

[person3024]

How do you answer questions about the effect of enthalpy and entropy on the reactions

legit i cant do this

 

[pancake15]

How do you answer questions about the effect of enthalpy and entropy on the reactions

Usually reference to the gibbs free formula resulting and the resulting gibbs free value (spontaneous/not) - which is basically same as the table (the one w entropy vs entropy and the boxes state spontaneity)

ie combustion of octane (GIVE EQUATION) - enthalpy of combustion is always negative, and since the number of gaseous molecules is larger in the products and the reactants (/no. of molecules of products overall) entropy is gained when combustion is undergone. Since enthalpy is negative and entropy is positive the reaction will be undergone spontaneously as gibbs free is negative, and then adjust accordingly depending on the reaction they give + enthalpy/entropy values (if they give both + the gibbs free value, basically it's the same ans but include the given values - ie BECAUSE enthalpy is (negative/positive value) and entropy is (negative/positive value), this yields the negative/positive value (whatever they provide) thus the rxn will be spontaneous/non spontaneous

if it's not clearly spontaneous/non spontaneous reference what temps it will be spontaneous at using the table, if they give gibbs free but its like ie small positive enthalpy and large positive entropy to give a negative gibbs free value, u can say rxn is entropy driven and vice versa if it doesnt adhere to the typical negative enthalpy positive entropy rule

 

[pancake15]

legit i cant do this

How do you answer questions about the effect of enthalpy and entropy on the reactions

notes from my summary attatched, idk if they'll be of any use but this is normally my approach

 

[Pac574]

what paper had the hardest multis, 2021 ?

 

[pancake15]

what paper had the hardest multis, 2021 ?

idk prolly given 2021 was the hardest paper, but the 2019 additional questions has some pretty hard ones

 

[person3024]

notes from my summary attatched, idk if they'll be of any use but this is normally my approach

lifesaver

 

[pancake15]

lifesaver

np
lmk if u need anything else, happy to help

 

[compd]

idk prolly given 2021 was the hardest paper, but the 2019 additional questions has some pretty hard ones

2020 was the hardest paper, not 2021

 

[femboys4life]

is skeletal formula accepted

 

[Pac574]

is skeletal formula accepted

Yes, there are many sample responses in HSC papers where they use this form

 

[shoulfer]

is skeletal formula accepted

yep but I would only use it within a response not as your final answer, for your final answer as a molecule id say to stick to structural

 

[ManifestationIsKey]

is skeletal formula accepted

Yes it is accepted. It is still a universal way of representing the structure, but as @shoulfer said, it would be preferred to stick to structural, but I doubt they would penalise for having a skeletal structure

 

[tiredcloud]

Where can I find the 2019 NESA practice questions, they don't seem to be on their website?

 

[Pac574]

Where can I find the 2019 NESA practice questions, they don't seem to be on their website?

Here it is : https://educationstandards.nsw.edu....al-sample-hsc-questions.pdf?MOD=AJPERES&CVID=

 

[pineapple546]

help!! how do u solve this??

 

[willy_g0706]

View attachment 45638
help!! how do u solve this??

can do the calculation but H+ in water = 10-7. that little of an acid will not change the pH

 

[Pac574]

What module do you guys recon will come up the most tomorrow? My mate from a selective school said Mod 6 & 8