HSC Chemistry Question Thread

[jakesilove]

When writing buffer equations, do you always make the acid react with H2O to form H3O+ ions and conj base
or do you react it with H3O+?

Always react an acid with water to show it's acidic properties, and a base with water to show its... basidic properties?

[RuiAce]

Always react an acid with water to show it's acidic properties, and a base with water to show its... basidic properties?

Jake, you've lost the most basic word from your vocabulary

[tennis1]

Always react an acid with water to show it's acidic properties, and a base with water to show its... basidic properties?

ohhh right yeah woops
so if it's a conj base I have to add the H3O+ but just generally write buffer equations using acid + water

[daatarz]

For Industrial chemistry, 31. a ii) in 2015 http://www.boardofstudies.nsw.edu.au/hsc_exams/2015/exams/2015-hsc-chemistry.pdf

Is the equilibrium constant calculated using halved values because the volume has been doubled?


Also, is their anywhere I can find written solutions because for some HSC past papers honestly the solutions are really bad/way too short and simple imo

[MysteryMarker]

For the formula H= -mCAT, should the mass be in g or Kg, and the H in J or KJ?

Cheers.

[anotherworld2b]

I was wondering is benzene a aromatic? What is the definition for a aromatic?
Also for addition reactions such as for pentane + Cl2 where do you put the cl in a structural formula? (is there a rule?)

[bethjomay]

Jake, you've lost the most basic word from your vocabulary

I lolled. Also: you could say the number of pages on this forum is about to get transuranic. 

[jakesilove]

For Industrial chemistry, 31. a ii) in 2015 http://www.boardofstudies.nsw.edu.au/hsc_exams/2015/exams/2015-hsc-chemistry.pdf

Is the equilibrium constant calculated using halved values because the volume has been doubled?


Also, is their anywhere I can find written solutions because for some HSC past papers honestly the solutions are really bad/way too short and simple imo

Sorry, gonna have to wait for someone that did Industrial!

[jakesilove]

For the formula H= -mCAT, should the mass be in g or Kg, and the H in J or KJ?

Cheers.

Check the constant that you use! Look at the value of C on your formula sheet; it will either be in g or kg, J or kJ. Whatever the units of the constant are, are the units you need to be using!

[jakesilove]

I lolled. Also: you could say the number of pages on this forum is about to get transuranic. 

I laughed for a long, long time

[jakesilove]

I was wondering is benzene a aromatic? What is the definition for a aromatic?
Also for addition reactions such as for pentane + Cl2 where do you put the cl in a structural formula? (is there a rule?)

No idea. Google tells me that Benzene is Aromatic.
As far as I'm aware, there isn't a rule, put them wherever you want

[RuiAce]

For Industrial chemistry, 31. a ii) in 2015 http://www.boardofstudies.nsw.edu.au/hsc_exams/2015/exams/2015-hsc-chemistry.pdf

Is the equilibrium constant calculated using halved values because the volume has been doubled?


Also, is their anywhere I can find written solutions because for some HSC past papers honestly the solutions are really bad/way too short and simple imo

Yeah that's why I used Excel Success One.

And regarding your question, yep exactly. Recall that the formula for the equilibrium constant uses concentrations, not moles. So if V = 2, then C = n/V = n/2

For the formula H= -mCAT, should the mass be in g or Kg, and the H in J or KJ?

Cheers.

Yeah as Jake said you really need to watch out for the constants in what C you use.

This is why I always write my units in my equations. I force things to cancel out properly.

[anotherworld2b]

oh okay thank you
I am not sure how to do the complete hydration of but-1-yne?

[RuiAce]

oh okay thank you
I am not sure how to do the complete hydration of but-1-yne?

Alkynes are in the HSC either I'm afraid.

[WLalex]

Do we have to draw all diagrams in pencil? I am worried that it will not scan well