mc problems-help. (1 Viewer)

[paper cup]

2001 specimen paper
8 Another student was dissatisfied with the results obtained by the four students and
wished to improve the reliability of the results. How could this be done?
(A) By asking the students to be more careful
(B) By carrying out the experiment under a variety of conditions
(C) By having each student repeat the experiment a number of times
(D) By making sure that the experiment is carried out under the same conditions

Would it be C or D? Reliability is concerned with consistency of results...

This is regarding q 3 of the mc for 2004. Why can't Mg, Zn and Al be identified with a flame test? Is there a reason why only the transition metals have coloured flames?
For 2003 mc q - this is unfamiliar stuff. Other than guessing the answer, which I did playing around with the only values given - molar mass and heat of combustion how would you work this out. delta H = cm delta T. But alas, no T, no m...

Is it just me or did the mc questions get harder from 2003 on? Like I breezed through 2001 and 2002 and then I get to 2003 and get stuck on some of the first qs...and I have done them before...ah god I am seriously screwed

 

[Captain Gh3y]

Reliability = repetition
Validity = conditions

C.

For the 2003 one: They give you the Heats of combustion in kJ per gram, and want to know which one has 2016 as kJ/mol, so you just multiply each of the given ones (22.7, 29.6...) by the molar mass of that compound and see which one gives you 2016.

Say a compound has a heat of combustion of 5 kJ/gram, and it has a molar mass of 10 grams per mole, it would therefore have a heat of combustion of 50kJ/mol, since burning one mole would be equivalent to burning 10 grams.

 

[paper cup]

Reliability = repetition
Validity = conditions

C.

For the 2003 one: They give you the Heats of combustion in kJ per gram, and want to know which one has 2016 as kJ/mol, so you just multiply each of the given ones (22.7, 29.6...) by the molar mass of that compound and see which one gives you 2016.

but where is this in the syllabus. it's weird. I know, I just played around with the numbers until i got one that fit/
and what about 2004?
you're a very good boy mummy loves you very much

 

[Captain Gh3y]

It's part of the experiment, converting from kj/g to kj/mol, I guess.

For 2004, it has something to do with atomic shells and electrons and excitement or something physics-esque that I can't think of now; at any rate we don't really NEED to know -why- only transition metals give a coloured flame. It'd be google-able if your life depends on finding out.

...

you're a very good boy mummy loves you very much

*faints*

 

[paper cup]

It's part of the experiment, converting from kj/g to kj/mol, I guess.

For 2004, it has something to do with atomic shells and electrons and excitement or something physics-esque that I can think of now; at any rate we don't really NEED to know -why- only transition metals give a coloured flame. It'd be google-able if your life depends on finding out.

...


*faints*

what don't you want me as your mummy, ungrateful twat you are

molar heat of combustion? but it's weird. it's so weird. and the difficutly with the mcs increasing - just me?

 

[Captain Gh3y]

what don't you want me as your mummy, ungrateful twat you are

molar heat of combustion? but it's weird. it's so weird. and the difficutly with the mcs increasing - just me?

You're so weird! It must just be you then.

 

[paper cup]

You're so weird! It must just be you then.

grr answer my question properly, I have to get off and this will plague my sleep and bring me bad bad dreams

 

[Captain Gh3y]

Fine. No, it's not directly in the syllabus but neither's everything else since then the 'syllabus' would just be a 5000 page list of all possible exam quesitons; the question involves the basic concept of what a mole/gram is.

The multiple choice questions are probably not intentionally being made harder every year, seeing as how hardness is largely subjective and even if there were some way of objectively measuring difficulty and then calculating the mean/median/mode/range of all the questions from 2001 - 2004 and then presenting the findings in a nice little graph, maybe with...

Anway, the point is, yes, they are getting harder, it's part of a conspiracy to make us all spend about 45 minutes trying to decide which box to colour in so the aliens can find out how our brain works.

Now go to sleep and dream about molar heat of combustion... I know I do.

 

[Dreamerish*~]

I don't think the multiple choice are getting harder. You just have to find the best answer out of 4, all of which could be right in some way.

 

[rnitya_25]

dremerish who that in your pic this time......kirsten looks way better.

 

[Dreamerish*~]

dremerish who that in your pic this time......kirsten looks way better.

Hey, don't diss Mrs. Depp.

She might not be as hot as Kristen, but she managed to convince Willy Wonka himself to marry her. So she ought to be congratulated and avatared by someone.

 

[rama_v]

I think for the reason why some metals can't be identified with falme tests is exactly as Captain said - energy sub shells and the arrangement of the electrons around the atom. I think people who do teh Chemistry of Art should know a lot more about this, but basically my guess is that the wavbelengths of light emitted by these metals are beyond the visible range of the spectrum.

 

[rnitya_25]

Hey, don't diss Mrs. Depp.

She might not be as hot as Kristen, but she managed to convince Willy Wonka himself to marry her. So she ought to be congratulated and avatared by someone.

lol.....are you serious?!?! mrs. depp....whoa.

 

[wanton-wonton]

Once again, according to the SUCESS ONE BOOK:

All four of the coices are appropriate: BLAH BLAH BLAH BLAH

 

[Haku]

Hey, don't diss Mrs. Depp.

She might not be as hot as Kristen, but she managed to convince Willy Wonka himself to marry her. So she ought to be congratulated and avatared by someone.

she look really ghastly. put on some one else

Edit: reading ur post now is a ghastly adventure now with that face appearing every time.

 

[paper cup]

Hey, don't diss Mrs. Depp.

She might not be as hot as Kristen, but she managed to convince Willy Wonka himself to marry her. So she ought to be congratulated and avatared by someone.

ohh she was a child star a singer vanessa paradis? what happened to her teeth
apparently when depp saw the back of her neck he knew he was utterly taken. is that her? I recall her being very very gorgeous

yeah I get it now, I think it's due to not having looked at chem for a long time.