multiple choice...WTF? (2 Viewers)

[~ ReNcH ~]

About the accuracy vs reliability thing, in the Success One Chemistry book one of the questions said how would you improve the accuracy of the experiment and the answer was to use repetition. These people write papers and mark them so why would they say that if the answer to the multiple choice question in our exam wasn't accuracy?

In that case I think Success One is incorrect. Repeating an experiment determines whether you get the same results again and again and again, hence reliability. Furthermore, in the exam there were two options: accuracy and validity, and they are virtually the same thing...so it couldn't have been either of them.

 

[holla back girl]

In that case I think Success One is incorrect. Repeating an experiment determines whether you get the same results again and again and again, hence reliability. Furthermore, in the exam there were two options: accuracy and validity, and they are virtually the same thing...so it couldn't have been either of them.

accurate: through use of very sensitive instruments
reliability:repetition
valid: is the experiment scientifically correct? are the variables controlled except for the one that you're testing?

 

[~ ReNcH ~]

accurate: through use of very sensitive instruments
reliability:repetition
valid: is the experiment scientifically correct? are the variables controlled except for the one that you're testing?

I stand corrected.

 

[jcl]

nah precision is achieved through use of sensitive instruments. accuracy is whether ur right or not. if u find gravity to b 50.32444243243242343243 ur damn precise but hopelessly inaccurate

 

[king_of_boredom]

okay, lookin at some anwsers, i gotta ask: 4 sulfuric acid log, isnt it b cause (H) is 0.1 times 2 cause is diprotic. that gives 0.2. then do -log(0.2) you get 1.
secondly, with ques 12, repeating improves accuracy! correct me if im wrong!

yeah for that question i just assumed complete ionization, the question shouldve been clearer. but yes the pH couldve been exactly OR less than 1. but i believe the right answer was less than 1.

 

[Kyroth***]

i put 2C
quote from the syllabus: "cellulose contains the basic carbon structure that can be converted to petrochemicals"

as well as option C says ORGANIC polymer

Yeah, but ALL polymers are organic, including pertochemical ones. Organic doesn't mean non-man made, it means it has carbons and hydrogens in it. Hence why I was sure it was A.

 

[cartzie]

Multi Choice

Hey guys and girls - i don't think the MC were too bad. I'm not sure about question 2 (i had d) and i'm not sure about the sulfuric acid one (i had c). My reasoning for c was because sulfuric acid isnt as strong as 0.1HCl which would have a pH of exactly 1. and since it is an acid it is less than 7. I didn't take into account the fact that it was diprotic cos i didnt come across anything in the syllabus that required us to know how to manipulate the log function for di/triprotic acids.

Other than those 2, i'm sure the rest of mine are right:
1) b (there are only 3 conditions for reactivity - none to do with electrons)
2) d (i have no idea)
3) b (2676 divided by molecular mass (74.12)
4) d (by observation)
5) b (Cu was the cathode [higher potential tha Al) and therefore reduction occurs so the blue colour of the copper solution would fade as they gain electrons and form a copper (reddish) precipitate on the copper electrode)
6) a (i seriously hope no one got that wrong)
7) c (apply Le Chatlier's principle to the CO2 equilibrium)
8) c (explained above)
9) d (i made an educated guess for this one + acetic acid is a weak acid therefore makes more sense)
10) c (another gimme question)
11) a (AAS only detects metallic ions)
12) b (yet another gimme)
13) c (u want the lowest numbers and the prefixes in alphabetical order)
14) d (i agree with the logic of previous comments on this answer [ie it is right]
15) a (same reason as Q14)

did you ppl think that the question about changing glucose to an ester required an extra long response?? i wrote a full page plus 2 and a bit pages from a writing booklet!!! and my answer could have still been more indepth!!.

 

[Dumsum]

did you ppl think that the question about changing glucose to an ester required an extra long response?? i wrote a full page plus 2 and a bit pages from a writing booklet!!! and my answer could have still been more indepth!!.

I wasn't aware you could use extra pages in that section. But yes, I did find it difficult to cram into that space.