Predictions for Chemistry 2014 HSC? (2 Viewers)

[faisalabdul16]

http://www.boardofstudies.nsw.edu.au/hsc_exams/hsc2006exams/pdf_doc/chemistry_06.pdf

Wtf Q11... I would have never gotten the answer (check BOSTES answers I don't want to spoil here). If anything those concepts are the result of Arrhenius' definition not that Arrhenius explained them

What's wrong with it? The answer is correct...

 

[SuchSmallHands]

Why is complete combustion favoured over incomplete? 3 marks

Complete combustion does not involve the emission of CO (equations for complete and incomplete combustion here). In the human body, CO combines with haemoglobin to produce carboxyhaemoglobin, which prevents the haemoglobin from transporting oxygen to body tissues, thus leading to comas, seizures and fatalities. Lower level CO poisoning can cause neurological effects such as disorientation, lack of balance and confusion as well as nausea and fatigue. Thus, it is preferable that CO emission are minimal, therefore complete combustion is preferable to incomplete combustion.

 

[Triage]

What's wrong with it? The answer is correct...

yeah? what is wrong with that? D is obvious isn't it?

 

[QZP]

Care to explain? My understanding is that strong/weak acid is the degree of ionisation in solution of an acid. This had no meaning before Arrhenius' theory. (e.g. What does degree of ionisation in solution matter for Lavoiser's definiton?)

Edit: To clarify what I mean, the answer is saying "Arrhenius' definition was an improvement as it explained why some acids are weak/strong". Now read what I said above. Arrhenius introduced concepts of weak/strong so I don't understand lol

 

[Triage]

Care to explain? My understanding is that strong/weak acid is the degree of ionisation in solution of an acid. This had no meaning before Arrhenius' theory. (e.g. What does degree of ionisation in solution matter for Lavoiser's definiton?)

Edit: To clarify what I mean, the answer is saying "Arrhenius' definition was an improvement as it explained why some acids are weak/strong". Now read what I said above. Arrhenius introduced concepts of weak/strong so I don't understand lol

I disagree. Humans have known for a long time that a fundamental difference exists between nitric acid and say citric acid. That is reflective of a primitive understanding of strong and weak acids that was later clarified by Arrhenius.

 

[QZP]

alright gg band 5 for me. i must have english problems if im the only one that doesnt understand it

 

[timeflies]

For people that do industrial, was diaphragm process developed after the mercury or before?

 

[zhertec]

After as the mercury cell was causing environmental hazards (mainly mercury) and required too much electricity to produce NaOH

 

[QZP]

For people that do industrial, was diaphragm process developed after the mercury or before?

The HSC takes it as after. But conq. chem if I recall says before. Go with what HSC wants though

 

[timeflies]

The HSC takes it as after. But conq. chem if I recall says before. Go with what HSC wants though

Yea one of the success one answers said before as well and I got confused, thanks for that

 

[emilios]

Industrial bros

Say you're conducting an electrolysis of NaCl in one of those U-tube thingoes. Products you get will be the hydrogen gas at the cathode as well as hydroxide ions in solution. At the anode: I know this depends on the concentration of the NaCl, but is there ever a time where you get a mixture of both chlorine and oxygen? Success One says you do but I'm skeptical.

 

[zhertec]

Industrial bros

Say you're conducting an electrolysis of NaCl in one of those U-tube thingoes. Products you get will be the hydrogen gas at the cathode as well as hydroxide ions in solution. At the anode: I know this depends on the concentration of the NaCl, but is there ever a time where you get a mixture of both chlorine and oxygen? Success One says you do but I'm skeptical.

You can get oxygen, but at a much higher voltage due to the difficulty of interaction between the water molecules and the anode, in terms of industrial, due to the high amounts of electrical used, you can definitely get a mixture of both. But in terms of the school lab, it's chlorine gas.

 

[zhertec]

Anyone else not feel like studying even though it is less than 15 hours away?

 

[Emma Watson]

u guys are asking too easy questions.

 

[Emma Watson]

i hope tomorrow exams is as easy as last year.

 

[QZP]

How do you guys draw your structural diagram for a polymer? Just [one unit]n? Do we have to include the initiator? I'm confused about whats on the left and right

 

[enigma_1]

How do you guys draw your structural diagram for a polymer? Just [one unit]n? Do we have to include the initiator? I'm confused about whats on the left and right

draw at least 3 monomer units. I don't think you need the initiator

http://upload.wikimedia.org/wikipedia/commons/f/f7/Polyethylene-repeat-2D-flat.png

 

[zhertec]

Replace the initiator with just the monomers free bonds sticking out of the brackets and then on the right it's the same thing but with an n on the bottom right side.

 

[QZP]

draw at least 3 monomer units. I don't think you need the initiator

http://upload.wikimedia.org/wikipedia/commons/f/f7/Polyethylene-repeat-2D-flat.png

Do I put a square bracket [ ]n around the 3 monomers? Or the middle one

 

[Cleavage]

i hope tomorrow exams is as easy as last year.

Emma Watson will you come to the formal with me