HSC 2012-2015 Chemistry Marathon (archive) (5 Viewers)

[Kaido]

re: HSC Chemistry Marathon Archive

I often see an accompaniment of data tables and diagrams with these 5-6 mark Qs, so yeah :O

I would say
. AAS enables us to detect traces of heavy metals that are often extracted from mining sites
. Will summarise how AAS works, especially calibration graph and absorbance -> to determine minute concentrations of heavy metals etc.
. Will consider the disadvantages, e.g. tedious if we want to measure a lot of different cations (which we do, esp near a mining site)
. Subsequent use of data in safeguarding environment -> we can determine necessary measures to reduce heavy metal pollution since it affects organisms (bioaccumulates and often poisonous)
. Judgement: AAS is effective in determining the necessary measures to safeguard our env. by determining the conc. of heavy metal pollution near mining sites

Let me know your answer plox

 

[Librah]

re: HSC Chemistry Marathon Archive

So in other words in the activity series if a metal all the way at the top is dipped into a solution all the way from the bottom nothing will happen or would the ions build up on the metal thats being dipped in ?

Don't understand what you just said, but i don't think so. What does "at the top" mean?

 

[Drsoccerball]

re: HSC Chemistry Marathon Archive

Don't understand what you just said, but i don't think so. What does "at the top" mean?

dw :L lets say if i have If i add an acid would the equilibrium shift to the the right or left abit confused because carbonic acid is acidic so shouldnt the equilibrium shift to the the right ?

 

[Librah]

re: HSC Chemistry Marathon Archive

dw :L lets say if i have If i add an acid would the equilibrium shift to the the right or left abit confused because carbonic acid is acidic so shouldnt the equilibrium shift to the the right ?

Adding H2CO3? Yes would shift to the right.

 

[Drsoccerball]

re: HSC Chemistry Marathon Archive

Adding H2CO3? Yes would shift to the right.

Not H2CO3 but just an acid ?

 

[Crisium]

re: HSC Chemistry Marathon Archive

dw :L lets say if i have If i add an acid would the equilibrium shift to the the right or left abit confused because carbonic acid is acidic so shouldnt the equilibrium shift to the the right ?

Shift to the left

Adding acid or in this case H3O+ will increase the concentration of products (Since the concentration of H3O+ is increased) hence shifting equilibrium to the opposite side (i.e. The left)

 

[ma2shah]

re: HSC Chemistry Marathon Archive

is the acid H2co3? If it is, to the right...

If the acid is a random acid, it creases concentration of hydronium ions and the equlibrium shift to the left.

 

[Librah]

re: HSC Chemistry Marathon Archive

Not H2CO3 but just an acid ?

Your adding another acid, so your introducing a new equilibrium to the system involving the acid you added. I don't think you can actually predict what will happen using HSC chemistry, since your only given very sandbox definitions of equilibrium in the HSC. Probably just say it shifts to the left.

 

[Crisium]

re: HSC Chemistry Marathon Archive

Your adding another acid, so your introducing a new equilibrium to the system involving the acid you added. I don't think you can actually predict what will happen using HSC chemistry, since your only given very sandbox definitions of equilibrium in the HSC. Probably just say it shifts to the left.

You can predict it...

When they say an "Acid is added" you have to assume that this acid has the H3O+ ion despite the fact that the acid being added not actually having this ion

Scroll above for my explanation

 

[Librah]

re: HSC Chemistry Marathon Archive

You can predict it...

When they say an "Acid is added" you have to assume that this acid has the H3O+ ion despite the fact that the acid being added not actually having this ion

Scroll above for my explanation

What

The acid does dissociate in water to provide H3O+ ions, but your changing the equilibrium. It's no longer going to be just H2CO3+H2O<-->H3O++HCO3-
Instead your also going to have some other ACID+H20<-->H3O+ +ion. How will you predict which equilibrium will be more spontaneous?

 

[Crisium]

re: HSC Chemistry Marathon Archive

What

The acid does dissociate in water to provide H3O+ ions, but your changing the equilibrium. It's no longer going to be just H2CO3+H2O<-->H3O++HCO3-
Instead your also going to have some other ACID+H20<-->H3O+ +ion. How will you predict which equilibrium will be more spontaneous?

Not sure what you mean by spontaneous when we're talking about which side equilibrium will favour

 

[Crisium]

re: HSC Chemistry Marathon Archive

What

The acid does dissociate in water to provide H3O+ ions, but your changing the equilibrium. It's no longer going to be just H2CO3+H2O<-->H3O++HCO3-
Instead your also going to have some other ACID+H20<-->H3O+ +ion. How will you predict which equilibrium will be more spontaneous?

Not sure what you mean by spontaneous when we're talking about which side equilibrium will favour

I think what you're talking about only matters when you're talking about something similar to the carbon dioxide - water equilibrium, and not in this situation:

View attachment 32130

 

[Librah]

re: HSC Chemistry Marathon Archive

Not sure what you mean by spontaneous when we're talking about which side equilibrium will favour

I think what you're talking about only matters when you're talking about something similar to the carbon dioxide - water equilibrium, and not in this situation:

View attachment 32130

That's assuming the only H3O+ is added, (which technically is a strong acid), but is impossible. Also nothing actually goes to completion, the equilibrium still exists even if one side has products that are say 10x10^-40 mol/L.

I'm saying in ALL equilibrium, not just acid-base.

 

[Crisium]

re: HSC Chemistry Marathon Archive

ffs can someone confirm which answer is correct?

 

[Drsoccerball]

re: HSC Chemistry Marathon Archive

An acid produces hydronium ions so crisium is right from my knowledhe

 

[Crisium]

re: HSC Chemistry Marathon Archive

An acid produces hydronium ions so crisium is right from my knowledhe

Confirmation from a future state ranker

I think we can finally move onto the next question

 

[Drsoccerball]

re: HSC Chemistry Marathon Archive

Confirmation from a future state ranker

I think we can finally move onto the next question

LOL you high ?

 

[Crisium]

re: HSC Chemistry Marathon Archive

LOL you high ?

heuhuehue

Post the next question up

 

[Drsoccerball]

re: HSC Chemistry Marathon Archive

2 Marks

 

[Librah]

re: HSC Chemistry Marathon Archive

ok..