enigma_1
~~~~ Miss Cricket ~~~~
Brahh don't post the questions like that. I can't access it on my phone.
Brahh don't post the questions like that. I can't access it on my phone.
hahaha -.- get on your computerBrahh don't post the questions like that. I can't access it on my phone.
I'm out, I can't teleport. :/hahaha -.- get on your computer
This one is really hard to do succinctly, since it targets collaboration, monitoring and management and electrochem. I'll try to do it as succinctly as possible for the 5-6 range (and probably fail...)yall need to start sticking to concise responses... that number of lines is about a 20 mark question
My answer for that question took 8 minutes thinking and typing. Handwriting it would probably take a little longer, around 10 minutes all up?Would you actually write that much though? And how long would it take you to do so? Please don't say 2 minutes :/
Marking criteria (6 marks)http://www.boardofstudies.nsw.edu.a...s/pdf_doc/chemistry-hsc-sample-answers-12.pdf
Everyone read the sample answer they have provided (Question 33).
It's not even worth 6 marks, max i would give is 4, and that's me being very lenient.
Ohyeah obviously they'd get a 6 because the sample answer addresses the marking criteria, whereas us, in an exam have no clue as to how to structure or where to get the 6 marks from. Come on, as if you're not going to brain dump everything you know in detail in order to ensure your 6 marks.Marking criteria (6 marks)
• Demonstrates a thorough knowledge and understanding of the identified
roles of chemists and the environmental impact of a correctly named
electrochemical cell
• Assesses the need for collaboration between chemists
• Demonstrates coherence and logical progression of ideas with correct
scientific terminology used
I think I'd give them six based off the criteria. I think they actually satisfied that criteria better than some of us, since we all veered more strongly toward reaction equation/mechanism of environmental impact (you know, like, chemistry?) rather than listing off a bunch of chemical professions which is where the marking criteria gives out a lot of it's marks. They listed four types of chemist, one more than any of us listed. But that's not to say that the marking criteria for this question was perfect, and I don't really think it was.
Not necessarily true, you have to be really careful not to take them as definite full mark answers according to my teacher. I guess that's why they have this caveat on the first page every year: 'the ‘sample answers’ or similar advice contained in this document are not intendedOhyeah obviously they'd get a 6 because the sample answer addresses the marking criteria, whereas us, in an exam have no clue as to how to structure or where to get the 6 marks from. Come on, as if you're not going to brain dump everything you know in detail in order to ensure your 6 marks.
We have no idea of what the marking criteria is, hence why we all go in so much detail and we have to.
A buffer is a solution which is made of equimolar amounts of an acid with its conjugate base (weak acid) and its role is to withstand pH change when small amounts of an acid or base is added. An example of a buffer in a natural system is the carbonic acid buffer, which helps to try and maintain the pH of blood at 7.4, to allow for enzymes in our body to operate at optimum capacity and allow for metabolic functioning.Explain how a buffer works with reference to a specific example in a natural system. (4 marks)
- Equimolar? That's not necessarily trueA buffer is a solution which consists of equimolar amounts of an acid with its conjugate base (weak acid preferentially) and its role is to withstand pH change when small amounts of an acid or base is added. An example of a buffer in a natural system is the carbonic acid buffer, which helps to try and maintain the pH of blood at 7.4, to allow for enzymes in our body to operate at optimum capacity and allow for metabolic functioning.
H2CO3(aq) + H2O(l) (equilibrium) HCO3(-) + H3O(+)
As carbon dioxide concentration increases, it dissolves with water forming carbonic acid, and the buffer is there to withstand the pH change and not allow for a decrease in pH. Without a buffer like such, there would be fluctuations in blood pH, resulting in enzymes either ceasing to exist or denaturation, leading to decreased metabolic functioning.
Bold part - i worded it wrong. It is made of equimolar amounts of acid and base.- Equimolar? That's not necessarily true
- Buffers only apply to weak acids/bases because it involves an equilibrium system
- You didn't explain how a buffer works (didn't answer the Q)
True that. A buffer is a solution consisting of a weak Bronsted-Lowry acid or base and its conjugate. The buffer is able to maintain pH despite the addition of small amounts of strong acid or base due to the system being in equilibrium.- Equimolar? That's not necessarily true
- Buffers only apply to weak acids/bases because it involves an equilibrium system
- You didn't explain how a buffer works (didn't answer the Q)
My equation shows it's in equilibriumTrue that. A buffer is a solution consisting of a weak Bronsted-Lowry acid or base and its conjugate. The buffer is able to maintain pH despite the addition of small amounts of strong acid or base due to the system being in equilibrium.
Didn't mention Le Chatelier once - disappointing.
You didn't specify how the CO2 is increased in concentration.
insert your equation here
You could say, via natural cellular respiration, humans inhale Oxygen and expel Carbon dioxide. By doing so, the carbon dioxide concentration in the blood decreases in the equilibrium ie the H2CO3 concentration decreases and since there is less CO2 dissolved, the pH increases because CO2 is the cause of acidity. And according to Le Chatelier's principle, when a system is in equilibrium and a stress is induced, the system will act in order to minimise the change and return the system to equilibrium. Thus, the system will shift to the left (reverse) direction to compensate for the reduced concentration of carbonic acid and this system acts as a buffer to allow the pH to be maintained within the range of 7.35 to 7.45 which allows the regular blood pH to be maintained, preventing decreased metabolism.
Ok QZP, how does this go- Equimolar? That's not necessarily true
- Buffers only apply to weak acids/bases because it involves an equilibrium system
- You didn't explain how a buffer works (didn't answer the Q)
k denMy equation shows it's in equilibrium
haha nah my answers is shit, i couldnt be bothered