HSC 2012-2015 Chemistry Marathon (archive) (1 Viewer)

[Drsoccerball]

re: HSC Chemistry Marathon Archive

Sorry for interrupting but I just wanna ask a question for clarification (it's probably a really simple question anyway), CFC is known to be inert so it is able to diffuse into the stratosphere without reacting in the troposphere, since it's inert, how does it react with ozone?

Under the presence of UV it reacts.

 

[Mr_Kap]

re: HSC Chemistry Marathon Archive

What is so bad about the chlorine monoxide radical?

 

[leehuan]

re: HSC Chemistry Marathon Archive

Chlorine monoxide radical allows the chlorine radical to be 'reborn'.

ClO + O -> Cl + O2

Dun dun dunnnnnn Cl is back

 

[Mr_Kap]

re: HSC Chemistry Marathon Archive

Chlorine monoxide radical allows the chlorine radical to be 'reborn'.

ClO + O -> Cl + O2

Dun dun dunnnnnn Cl is back

THe only thing that can save you now is greenhouse gases such as methane

 

[Drsoccerball]

re: HSC Chemistry Marathon Archive

THe only thing that can save you now is greenhouse gases such as methane

So start eating more baked beans = problem solved.
I should get a nobel prize tbh...

 

[leehuan]

re: HSC Chemistry Marathon Archive

Cl + CH4 -> HCl + CH3

But also

ClO + NO2 -> ClONO2

 

[BlueGas]

re: HSC Chemistry Marathon Archive

Cl + CH4 -> HCl + CH3

But also

ClO + NO2 -> ClONO2

Furthermore, during winter in Antarctica the HCl from the first equation reacts with ClONO2 from the second equation to form Cl2 and HNO3, this reaction has no effect on the ozone layer during winter but this changes dramatically during spring when the sun begins to rise and the rays split the chlorine molecule forming a chlorine radical.

 

[leehuan]

re: HSC Chemistry Marathon Archive

Furthermore, during winter in Antarctica the HCl from the first equation reacts with ClONO2 from the second equation to form Cl2 and HNO3, this reaction has no effect on the ozone layer during winter but this changes dramatically during spring when the sun begins to rise and the rays split the chlorine molecule forming a chlorine radical.

Damn that Antartic vortex.

 

[BlueGas]

re: HSC Chemistry Marathon Archive

Quick question, do the electrolysis methods each produce different types of NaOH? Or are they all the same?

Also how are Molten, conc, and dilute NaCl produced, is there a named method?

 

[Drsoccerball]

re: HSC Chemistry Marathon Archive

Quick question, do the electrolysis methods each produce different types of NaOH? Or are they all the same?

Also how are Molten, conc, and dilute NaCl produced, is there a named method?

The concentrated and dilute have the same cathode reactions but different anode reactions while molten has both different.

 

[BlueGas]

re: HSC Chemistry Marathon Archive

Describe the use of sulfuric acid as an oxidising agent, and as a dehydrating agent. Use chemical equations to illustrate your answer. (3 marks)

 

[Drsoccerball]

re: HSC Chemistry Marathon Archive

Describe the use of sulfuric acid as an oxidising agent, and as a dehydrating agent. Use chemical equations to illustrate your answer. (3 marks)

Dehydrating agent:

Oxidising agent:

Ceebs doing the rest

 

[BlueGas]

re: HSC Chemistry Marathon Archive

Dehydrating agent:

Oxidising agent:

Ceebs doing the rest

How would you describe each reaction in a simple way?

 

[Drsoccerball]

re: HSC Chemistry Marathon Archive

How would you describe each reaction in a simple way?

tbh for dehydration i would use ethanol. You can talk about how the water is extracted from the sucrose or ethanol. For copper you can calculate the change in oxidation state

 

[BlueGas]

re: HSC Chemistry Marathon Archive

tbh for dehydration i would use ethanol. You can talk about how the water is extracted from the sucrose or ethanol. For copper you can calculate the change in oxidation state

How about the reaction in the red box, is sulfuric acid actually acting as a dehydrating agent?

 

[Drsoccerball]

re: HSC Chemistry Marathon Archive

How about the reaction in the red box, is sulfuric acid actually acting as a dehydrating agent?

I guess so... But its better to have two different equations.

 

[BlueGas]

re: HSC Chemistry Marathon Archive

tbh for dehydration i would use ethanol. You can talk about how the water is extracted from the sucrose or ethanol. For copper you can calculate the change in oxidation state

So what's the reaction equation for this?

 

[Drsoccerball]

re: HSC Chemistry Marathon Archive

So what's the reaction equation for this?

For ethanol?
lol.

 

[leehuan]

re: HSC Chemistry Marathon Archive

Dehydration of hydrous copper sulfate is perfectly acceptable.

CuSO4.5H2O -(H2SO4)-> CuSO4 + 5H2O

It's also actually a rather good example as the sample changes colour from blue to white


Personally, I would do dehydration of sucrose though

 

[BlueGas]

re: HSC Chemistry Marathon Archive

For ethanol?
lol.

For sucrose, is the reaction in your previous post regarding sucrose? Or is that different reaction?