ATAR Notes: Forum
VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: tcg93 on September 23, 2010, 03:00:36 am
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Hey,
Could someone please help me with the following questions from the CSE 2006 paper (Unit 3 paper)- relevant for current Study Design
M/C- Q9 - why is the ans A? isn't it meant to be a net back reaction?
MC - Q14 - Why is it acting as an acid (D)? Where are the acid/base conjugate pairs?
SAQs - Q5
Water vapour (product) added - why does the forward reaction rate remain unchanged? - aren't both forward/back rates meant to increase with the back increasing more?
Edit: Questions attached
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Question 9, just apply le chatliers law.. since you add a base in, reaction will go in the net direction which will increase the acidity to partially oppose the change
Question 14, its definitely not a hydrating agent, oxidant no because theres no change in its oxidation number, which leaves only acid left , and since it has lost both its hydrogen atoms... its acted as an acid.
Hope that correct
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For 9 you got the net backward reaction bit right but you didn't read the answer properly A is the ion CH3CH(OH)COO-
The answer is C i think.
Didn't read what u were saying properly :P
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For 9 you got the net backward reaction bit right but you didn't read the answer properly A is the ion CH3CH(OH)COO-
The answer is C i think.
no, net forward reaction will decrease the ph, which will oppose addition of a base ?
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oops, yea =='
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For 9, you could say that H3O + and H+ are interchangeable right? so when you add NaOH the OH binds with the H+ therefore there needs to be a forward reaction as such A is correct.
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For 9, you could say that H3O + and H+ are interchangeable right? so when you add NaOH the OH binds with the H+ therefore there needs to be a forward reaction as such A is correct.
Ok, but how if you make that argument, then why isn't B the answer?
Can someone also help with 5.
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For 9, you could say that H3O + and H+ are interchangeable right? so when you add NaOH the OH binds with the H+ therefore there needs to be a forward reaction as such A is correct.
Ok, but how if you make that argument, then why isn't B the answer?
Can someone also help with 5.
Well as soon as they get formed they immediately get converted into water so doesnt increase or decrease.
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With 5: if you add a product, in order to return to equilibrium, the backwards reaction rate increases initially, and then gradually decreases to be equal to the forward reaction rate. There is no change in the forward reaction rate during this process.
Hope that makes some sense. :)
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Thanks guys