ATAR Notes: Forum
VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: Martoman on November 09, 2010, 06:53:06 pm
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2B, why do they replace the NH2COONH4 with a value of 1? (lol to avoid a quadratic equation I think)
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Not having seen the Q, I don't know, but if it is in a K equation, and is solid, solids are are assigned a conc of 1...
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I had the same issue! If they replaced it with one then the amount is already known! CONFUSION!
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Not having seen the Q, I don't know, but if it is in a K equation, and is solid, solids are are assigned a conc of 1...
The FUDGE?
That would imply that since the equlibrium mole is 0.385-x then x = -1.615.... LOL
Since when do we assign them 1?
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Not having seen the Q, I don't know, but if it is in a K equation, and is solid, solids are are assigned a conc of 1...
The FUDGE?
That would imply that since the equlibrium mole is 0.385-x then x = -1.615.... LOL
Since when do we assing them 1?
That's why I think TSFX exams are stupid! :P
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I haven't seen the Q, but solid species are assigned conc = 1. It is a rule...
You basically just ignore them.
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but but but but q 6 was sex on a plate
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I haven't seen the Q, but solid species are assigned conc = 1. It is a rule...
You basically just ignore them.
................lol............. its not in the textbook, lucky I found this out.
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A solid doesn't have a concentration...
Yep, I only found out thanks to KBT, very unusual question, hopefully we get it on Thursday, we'll be sweet!
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A solid doesn't have a concentration...
Yep, I only found out thanks to KBT, very unusual question, hopefully we get it on Thursday, we'll be sweet!
Yeah but thats just..... odd.
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A solid doesn't have a concentration...
Yep, I only found out thanks to KBT, very unusual question, hopefully we get it on Thursday, we'll be sweet!
Yeah but thats just..... odd.
I agree, I don't understand it, but I can apply it.
That's what VCE is about right? being able to answer questions on the exam correctly. lol.
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Is this exam worth doing?
Tomorrow I am doing VCAA 09 and NEAP 08.
What other exams are worth doing, if any?
I've done all the other NEAP/STAV and some Insight/Lisachem and KBT
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haha I learnt that solid thingy from Khan academy :P
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Daughter, I am disappoint. I mentioned it in here: http://vcenotes.com/forum/index.php/topic,29208.msg308165.html#msg308165
:P
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:-[ i've disappoint you quite a lot these few days.... yeah it makes perfect sense now
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Is this exam worth doing?
I think it is, because it illustrates some interesting points/ideas. Just don't take it to seriously if you do do it and don't let it affect your confidence. Irena writes so many questions that some of them can occasionally be a bit...off the mark.
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Gotta finish those tutes before Thursday Mao :P
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gahhhh not 2010, 2008 exam
Platinum electrodes are suspended into a 500ml solution containing the following ions
Ag+, Cu2+, Al3+, Ni2+. If the current was passed through the cell at constant voltage of 1.4, the last metal to be depositied onto the cathode would be
Ag
Cu
Al
Ni
So obviously Al is not, its below water. I say nickel but they say: To deposit Ni, and EMF of 1.46 V is required.. where did they get this EMF from?
in short their answer is Cu
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gahhhh not 2010, 2008 exam
Platinum electrodes are suspended into a 500ml solution containing the following ions
Ag+, Cu2+, Al3+, Ni2+. If the current was passed through the cell at constant voltage of 1.4, the last metal to be depositied onto the cathode would be
Ag
Cu
Al
Ni
So obviously Al is not, its below water. I say nickel but they say: To deposit Ni, and EMF of 1.46 V is required.. where did they get this EMF from?
in short their answer is Cu
i tried to find a reason where they got 1.46 but i failed.. i dnno mayb question seems dodgy.. i wud say Ni aswell..
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btw is the emf calculated like this 0.8+0.34+0.23 ..??
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I have no idea actually...
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Does it come from
O2 + 4H+ + 4e- ---> 2H2O +1.23V
Ni2+ + 2e- ---> Ni(s) -0.23V
-.23 + (-1.23) = -1.46 V
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Gotta finish those tutes before Thursday Mao :P
haha, yeah right... I will endeavour to finish those by next year. I totally underestimated how much work I had. I've finished two slabs of mother in the last 4 weeks. TWO SLABS. (48 cans, that's right)
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Mother is disgusting.
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Mother is disgusting.
yeh i hate mother.. i am all for 'V' .
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What's wrong with mother? just finished 2 slabs of V and 1 slab of mother right in time for exam period finish :D
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still don't really get this..
Similarly, if you have a voltage of 2V why can't water be deposited at the cathode of an electrolytic cell ala KBT tsmania jones question?
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I was always taught that in order to power a non-spontaneous reaction, you're going to need higher voltage than the EMF of both.
For the Tassy Jones one, electrolysis of water requires 1.23 - (-0.83) = 2.06V for the non-spontaneous reaction to go ahead, any lower and its going to do shit all
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Does it come from
O2 + 4H+ + 4e- ---> 2H2O +1.23V
Ni2+ + 2e- ---> Ni(s) -0.23V
-.23 + (-1.23) = -1.46 V
It's -.23 - (-1.23) = 1.46v.
If you get a negative EMF then the reaction won't be spontaneous and you won't have current through it.