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#81609 2002 - Written Paper - Q4(b)

Posted by Pyrefly on 25 May 2006 - 11:54 AM in Problem Questions

Well..im nto any good at chemistry....but i dont know where the 0.02 moles came from for the H2SO4....

moles= concentration * Volume


both acids have the same concentration and volume..so they surely have the same number of moles...

ya if someone would help out it be nice..im a tad confused here too



#81301 crash physics

Posted by Pyrefly on 24 May 2006 - 11:26 AM in Physics

My friend did crash higher this year. She went in to do int 2 and then move onto higher next year but there wasn't enough people for an int 2 class. So she decided to do crash higher.

In the prelim she got a B (only a couple of marks away from an A as well!) She did terrible in maths this year though....(wich is kinda strange as she took all three sciences tongue.gif)

If you are saying you got an A for your prelim for maths i dont think that physics should be too much of a problem. Just make sure you ask if there is anything that you dont understand (there is a few things from standard grade you will have to pick up on)

Personally Physics is my favourite subject. I dont find it borning at all (well...maybe the second unit was a little dull at times...im not a fan of electrical work)

So i would sujest you go for it tongue.gif






#81292 2005 - Multiple choice - Q16,23,34,40

Posted by Pyrefly on 24 May 2006 - 11:03 AM in Problem Questions

QUOTE(nathanm @ May 23 2006, 04:11 PM) View Post

if you wanna discuss this any further, i suggest you start a new topic wink.gif

anyway, to get back on topic,

hah...i know how to do question 40 biggrin.gif

and whoever said to ignore the first graph was on the right lines wink.gif

what you do is that you look at the 2nd graph and see that there is 25%...which means 2 half lives have taken place over the 8 days and therefore 1 halflife = 4days biggrin.gif



Ya i worked that much out smile.gif

The first line was the other 75%



#80984 2005 - Multiple choice - Q16,23,34,40

Posted by Pyrefly on 23 May 2006 - 09:31 AM in Problem Questions

QUOTE(Daron Malakian @ May 22 2006, 10:40 PM) View Post

in the final exam which i did last year i had no clue how to do some of the multi choice questions. however, this was not a problem because you just put a line through all 4 answers and, because a computer marks it and only checks if u have a line in the right box, the computer marks it right.

when my teacher broke my mark into sections i had full marks for section A.

that cant be right...otherwise you would get the whole of scotland with full marks for section A.

Does anyone know if the multi choice is in pencil this year like it was for Physics? Useing the graphite would show the computer exactly where you had marked and would not award you if you put it in all boxes.

Maybe you just had a fluke last year.



#80835 2005 - Multiple choice - Q16,23,34,40

Posted by Pyrefly on 22 May 2006 - 04:02 PM in Problem Questions

QUOTE(Pammy @ May 22 2006, 05:01 PM) View Post

QUOTE(Pyrefly @ May 22 2006, 03:58 PM) View Post


there is 75% on the first graph which is the amount that has been lost!
there is 25% on the second graph the amount that is left!

so...the 25% is 2 half lifes. And 8 days devided by the 2 half lifes means the half life is 4days

(basically you can ignore the first one....its just what has been lost...i think)


Ahhhh ok then!!! Thankyou biggrin.gif



I wouldn't trust that 100%...its just a theory tongue.gif

It works a little better than egnore the first graph..or devide 8 by 2 tongue.gif



#80832 2005 - Multiple choice - Q16,23,34,40

Posted by Pyrefly on 22 May 2006 - 03:58 PM in Problem Questions

QUOTE(Pammy @ May 22 2006, 04:41 PM) View Post

QUOTE(Pyrefly @ May 22 2006, 03:36 PM) View Post

Lets see....im gonna ignore the first line on the graph..since it confuses me tongue.gif


haha lol i like u !!! U think like me biggrin.gif
And maybe you are right !!! It's better than my '4 is half of 8' theory



lol thats just how these kinda things work...just like the theory of when your stuck at other multi choice....It must be an A! as there hasn't been an A in ageeess tongue.gif

OH!!! I GET IT!

there is 75% on the first graph which is the amount that has been lost!
there is 25% on the second graph the amount that is left!

so...the 25% is 2 half lifes. And 8 days devided by the 2 half lifes means the half life is 4days

(basically you can ignore the first one....its just what has been lost...i think)



#80819 2005 - Multiple choice - Q16,23,34,40

Posted by Pyrefly on 22 May 2006 - 03:36 PM in Problem Questions

Lets see....im gonna ignore the first line on the graph..since it confuses me tongue.gif

The second one is at 25% which is 2 half lifes. And The sample is 8 days old. that means that the half life is 4 days.

only thing that confuses me is what the first line is there for...just to look confusing?



#80814 2005 - Multiple choice - Q16,23,34,40

Posted by Pyrefly on 22 May 2006 - 03:34 PM in Problem Questions

QUOTE(Pammy @ May 22 2006, 04:26 PM) View Post

* tumbleweed blows in the wind *

No-one sure about Q40 then ?? rolleyes.gif
It's starting to annoy me mad.gif



lol.. *takes out calculator and starts pressing random numbers*

hmm....



#80810 2005 - Multiple choice - Q16,23,34,40

Posted by Pyrefly on 22 May 2006 - 03:22 PM in Problem Questions

Thats great! thanks alot biggrin.gif



#80805 2005 - Multiple choice - Q16,23,34,40

Posted by Pyrefly on 22 May 2006 - 03:14 PM in Problem Questions

QUOTE(nathanm @ May 22 2006, 04:02 PM) View Post

i really don't get Q40...there was something similar in my supp. prelim and i didn't understand it then rolleyes.gif



ya i had the same kind of question in my support prelum too...but that time i guessed the right answer...i really dont understand it...

Does anyone have a link to where i can find the definitions of each of the different things liek oxidation, condensation, hydrolosis....theres so many now im getting a little confused.

I remeber in standard grade learning LEO and REG

Losing electrons = oxidation
Reduction= electron gain

or was it something else....im a tad confused with Chemistry tongue.gif

also anyone had any idea about Q 40?



#80799 2005 - Multiple choice - Q16,23,34,40

Posted by Pyrefly on 22 May 2006 - 02:53 PM in Problem Questions

QUOTE(nathanm @ May 22 2006, 03:42 PM) View Post

16. 11.5l = 0.5mole = 3x1023 molecules

1 mole = 6x1023 molecules = 12x1023 atoms

0.5 mole = 6x1023 ...answer C

34. hydrogen will shift to the left, HCl will also shift to the left, NaCl again to the left, leaving NaOH which will shift equilibrium to the right... answer D


ahh....thats how it works....I 0.5 * 6(.02)*10^23...forgot that it 6(.02)*10^23 molecules which went to become 12*10^23 atoms

Thank you tongue.gif

just need help with the other two smile.gif



#80786 2005 - Multiple choice - Q16,23,34,40

Posted by Pyrefly on 22 May 2006 - 02:30 PM in Problem Questions

I need help on the following qustions from the 2005 MC.

Q16
Approcimetely how many atoms will be present in 11.5 litres of carbon monoxide?
(take the molar volume of carbon monoxide to be 23 litres mil^-1)
A 1.5*10^23
B 3*10^23
C 6*10^23
D 1.2*10^23


Q23
Oxidation of 4-methylpent-2-ol useing copper(II) oxide results in the alcohol
A losing 2g per mole
B gaining 2g per mole
C gaining 16g per mole
D no change in mass

Q34
Cant really type out the equilibreum ones..
Cl2 (g) + H2O (l) <----> Cl- (aq) + 2H+ (aq)
hopefully whoever helps has this past paper to look at rather than trying to decifer my attempt at showing the equilibrium.....
anyway...
The addition of which of the following substances would move the above equilibrium to the right?
A Hydrogen
B Hydrogen Choloride
C Sodium Chloride
D Sodim hydroxide
(I think i understand this one now..but it would be good to see a smart persons answer tongue.gif)

Q40
This one is a graph one...so also cant type it out.


Thanks in advance smile.gif



#80637 mole

Posted by Pyrefly on 21 May 2006 - 04:16 PM in Chemistry

o0 i dont get it....(yo there...someone whos about to fail chemistry here tongue.gif)

every time i try that i get 4*10^-5

care to explain to me further?



#80631 Grade Boundaries

Posted by Pyrefly on 21 May 2006 - 04:00 PM in Physics

Just a little more info...This firdays Herald gave details of English, Moden studies and French. Next firday will show teacher/pupil views on Physics, Maths and a couple of other subjects..cant remeber what.



#80629 How It Go?

Posted by Pyrefly on 21 May 2006 - 03:58 PM in Physics

QUOTE(Betinho @ May 21 2006, 01:03 PM) View Post

To be honest, I can only see the formula sheet being of real benefit to those looking for a C pass. Those looking for an A or a B pass (or maybe even a good C pass) will have done so much studying and calculations that it's kinda hard not to remember them all...

QUOTE(friendlyneutron)
I don't think I even used it.

Me neither.

I know what you mean. The only use for the data booklet for me for me was to ensure i had things right (i always get that sinking feeling that somethings wrong..it was nice to have something to look at to make sure i was right ;p)

Well that and the data book question. I felt sorry for some of the people in my Physics class. I asked the teacher once when we were doing radiation if you got a periodic table and he said you wouldn't. When i saw the question that asked you to find T or whatever...i felt sorry for those who didn't take chemistr. They wouldn't know what to look for on the table :-/

Though i guess it was only worth a mark or two ;p

im fairly confident I will get an A for physics...wish i could be so confident about maths....



#80052 How hard was it?

Posted by Pyrefly on 19 May 2006 - 01:34 PM in Mathematics

I was so sure this morning i was going to get a C for Maths (i got an ! for my preilum...support one didn't go so well so theres not much chance of an apeal) But paper one seemed to ok ok(ish)

Paper two was harder in my opinion. The -2 +2 thing kinda confused me alot tongue.gif

I reeeallly want to get an A but i get the feeling I will only get a B (or worse C sad.gif)



#80016 Higher Maths 2006

Posted by Pyrefly on 19 May 2006 - 12:41 PM in Mathematics

QUOTE(rscott @ May 19 2006, 01:37 PM) View Post

QUOTE(nathanm @ May 19 2006, 01:23 PM) View Post

QUOTE(rscott @ May 19 2006, 01:21 PM) View Post

What did everyone get for Q. 4, paper II ?

I got the radius of the other circle as root 13, so I said the radius of the larger circle was 5?



that's what i got biggrin.gif


Woohoo biggrin.gif

I really wasn't sure about that question, especially with the way it had been worded.


YEY! Im so happy i am not the only one who got that! My friend got something compeltly different (ans shes normally laods better than me at Maths..)

*sigh of relief* Hopfully that means another 5 marks to add to my total....



#79531 How It Go?

Posted by Pyrefly on 18 May 2006 - 11:43 AM in Physics

ok...from my random scribblings...i think i have 75%!! (thats excluding ones im not 100% sure about such as the capacitor one....)

biggrin.gif even if some of my scribles are wrong im pretty sure thats an A!

*does a little dance before remebering maths exam is tomorrow*
ahhh!! Im gonna fail maths!!



#79522 How It Go?

Posted by Pyrefly on 18 May 2006 - 11:25 AM in Physics

great biggrin.gif
another 2 marks ^^

oh theres one i found that we haven't poked at with a toothcomb yet! ;p

Q29 b) iv)

I got the mass lost to be 3.4*10^-28

Then shoved it in the E=mc^2 formula and got... 3.06*10^-11

Anyone else get this? smile.gif



#79520 How It Go?

Posted by Pyrefly on 18 May 2006 - 11:19 AM in Physics

Ya i know that tongue.gif

Its just that you didn't square root the final answer so I didn't have the same. The actualy answer is 6.2*10^6 i belive...it would be nice if someone would check that for me tongue.gif

(o0 weird double post on the same post...)



#79496 What grade do you think you got?

Posted by Pyrefly on 18 May 2006 - 10:07 AM in Physics

Im going for an A....i think im gonna be around the 68-72% mark though..so im just crossing my fingers the pass boundry for an A is at the lower end of that ;p




#79493 How It Go?

Posted by Pyrefly on 18 May 2006 - 09:58 AM in Physics

QUOTE(nathanm @ May 18 2006, 12:58 AM) View Post


24a) again, can someone enlighten me biggrin.gif

b) and again

ci) W= QV = 1.60x10-19 x 200000 = 3.2x1014

ii) v = sqrt.gif (2QV / m) = sqrt.gif (6.4x10-14 / 1.679x10-27 ) = 3.81x1013 ms-1

d) no effect as Q, V and m remain constant





I found why i have a different answer to you tongue.gif

I did basically exactly the same only did 0.5* the mass instead of 2* the energy.
The thing is....you didn't square root your final answer.
(also you have the mass of the proton slightly wrong its not 1.679x10-27 but rather 1.673x10-27 not that that would make a huge difference on your answer....)

Even with your mistake sqrt.gif 3.81x1013 = 6.172x106 (which i had rounded with the correct mass to 6.2)



#79486 How It Go?

Posted by Pyrefly on 18 May 2006 - 09:37 AM in Physics

*calculating*



#79467 How It Go?

Posted by Pyrefly on 18 May 2006 - 07:49 AM in Physics

QUOTE
ii) v = (2QV / m) = (6.4x10-14 / 1.679x10-27 ) = 3.81x1013 ms-1

(i dont know how you put your root signs in...it didn't copy when i did the quote thingy so..remeber theres roots in there if you want to see)


o0 im really confused by your answer how you got that...

I didn't get the same..
I said the Ek at the end of the Tube was the Work done at the start (maybe i went wrong here straight away actually...)

Ek = 1/2 mv^2
3.2*10^-14 = 0.5 * 1.673*10^-27 *v^2
V^2 = 3.2*10^-14/ 0.5 * 1.673*10^-27
V = root of the above....
V = 618503.934
= 6.2*10^6


can someone direct me to where i am wrong? where did your 2QV come from? should it not be 1/2 rather than 2?

hmmm....*is confused*



#79356 How It Go?

Posted by Pyrefly on 17 May 2006 - 08:18 PM in Physics

I wouldn't nessecaraly listen (well read) what i said tongue.gif I didn't have a clue..?I just guessed tongue.gif