Answers To Difficult Questions (4 Viewers)

[!!!akittelty!!!]

For the bottles i got
1 HCL
2 Na SO4
3 PBNO3
4 BANO3

but i think i got the last 2 around the wrong way

 

[Martyno1]

No need to be sorry joshyputts. cos the answer is d.
white light isnt used in aas. they only use the one wavelength and measure how much of that is absorbed. otherwise other elements would interfere with results. the wavelength they use is the one that the specific element absorbs, the same one it emits in a flame test.

ok you have provided the most logical explanation so far lol

 

[Martyno1]

For the bottles i got
1 HCL
2 Na SO4
3 PBNO3
4 BANO3

but i think i got the last 2 around the wrong way

well there was no NaSO4 anyway...

 

[JoshyPutts07]

Guys we all smart so dont worry we all do well lets concentrate on the exams ahead !

haha your right
nothing we can do now
lets just get this shit over and done with

 

[JoshyPutts07]

No need to be sorry joshyputts. cos the answer is d.
white light isnt used in aas. they only use the one wavelength and measure how much of that is absorbed. otherwise other elements would interfere with results. the wavelength they use is the one that the specific element absorbs, the same one it emits in a flame test.

kk my bad, just re-read the question, yeh i was tossing up between C and D but that flame test bit in D confused me a bit and I wasn't sure whether that could actually vaporise some of the atoms that all...........So i ended up going with D

oh well, nothing I can do now, To be honest, I really don't care haha
as long as I don't get a mystery mark that is :mad1:

 

[appleide]

But the definitipn of a catalyst (at least from BOS) is one that doesn't affect the position of the reaction, just lowers the activation energy required.

The free radical is an initiator, just like in addition polymerisation.

Also, what did you guys get for the ppm of Cl in water? I had like 29000 ppm

I got 28XX0 ppm..... so I think we're about right, but you did more rounding than me.
Hmm.... I might also have gotten 18XX0 can't remember now.

I put chlorine as an initiator, but then went to several textbooks, all said it was a 'catalyst' :S.... And I thought I should follow the 'Catalyst don't involve themselves in the reaction, they only lower the activation energy' definition I saw elsewhere.

 

[joshuajspence]

did anyone finish with ages to go?

i had an hour... and im pretty sure i checked all my worked. but im worried i missed a question. i recgonise all the ones uv been tlkn about in this forum which is good

 

[gadbil]

hey guys what did use get for question 6 9 10 12

 

[lil dynamyt]

Hey,

For those that do the option industrial chem,

What was the experiment that models an equilibrium reaction???

 

[appleide]

I *knew* I would finish with ages to go if I do it normally, so I decided to instead, use most of three hours writing really neat handwriting and re-reading the question 2-3 times and my answer double checked after each question so I won't make any silly mistakes.... It works better for me that way. Don't know about you though.

 

[joshuajspence]

hey guys what did use get for question 6 9 10 12

6C
9A
10C
12A

 

[NJMORTIMER]

Catalysts can and often do involve themselves in chemical reactions (that is how they lower the activation energy, breaking bonds etc). The significant thing is that they are reformed in the end.

 

[gadbil]

isnt question 6 a

 

[joshuajspence]

Hey,

For those that do the option industrial chem,

What was the experiment that models an equilibrium reaction???

omg i was just gonna ask this... i didnt know if it meant an equipment... because it said "You have performed a first-hand investigation to model an equilibrium reaction"

i said the SCN- Fe3+ equilibrium reaction but thats an experiment

 

[gadbil]

oh sorry ignore me it cant be [a] lol

 

[Forbidden.]

sorry guys, pretty sure that AAS one was C.........B is wrong as "vaporised atoms falling down to their ground state" sounds bit more like chemiluminescence, and for AAS why would they need to fall donw to their ground state anyway?, C was most logical

White light is a continuous spectrum.

 

[joshuajspence]

isnt question 6 a

phenolphthalein is colourless below ph 8.2 and pink above pH 10

 

[gadbil]

why is question 9a

 

[joshuajspence]

why is question 9a

citric acid is an acid. from this we get the conjugate base citrate. sodium citrate contains the citrate acid, which is the conjugate base of citric acid

sodium chloride is neutral.

ammonium is the conjugate acid of the base ammonia, hence they are acidic

 

[gadbil]

oh ok damnn i wish i can go bak in tym i hate mc