[Chemistry] - Challenge for 'O' & 'A' Level Students
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Here's a chemistry calculations question I wrote just the other day, to let my students (both 'O' and 'A' levels) enjoy a bit of fun with chemistry calculations. I challenge all 'O' and 'A' level students on this forum (including lurkers) to solve this question. If you can, post your worked solution here (as proof you solved it). If you're unable to upload your solutions, at least you still have the satisfaction of solving it yourself on paper. ~ A BedokFunland JC Original Calculations Challenge ~ 50cm3 of aqueous sulfuric(VI) acid of unknown molarity was mixed with 75cm3 of 0.45mol/dm3 of aqueous potassium hydroxide. 55cm3 of the resulting alkaline solution A was mixed with 80cm3 of 0.35mol/dm3 of phosphoric(V) acid. 90cm3 of the new resulting acidic solution B required 39.97cm3 of aqueous sodium carbonate of unknown molarity, for complete neutralization. In a separate experiment, 625cm3 of the same aqueous sulfuric(VI) acid solution required 192.3cm3 of the same aqueous sodium carbonate solution for complete neutralization. Calculate the molarities of the sulfuric(VI) acid solution and the sodium carbonate solution. Answers : [H2SO4] = 0.2 mol/dm3 [Na2CO3] = 0.65 mol/dm3
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*stares at question and resolves to solve it later. xD -
-reserve post-
tmr den do . so freaking complicated need alot time xD
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wa this looks uber hard....
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Originally posted by absol:
wa this looks uber hard....
Just make sure u understand the question 1st. Yihao had a few misconceptions and i dunno about any of the rest who are willing to even try.
Just be prepared to do simultaneous equations i believe and have fun forming your equations which won't be easy.
Since the answers are already given, 1 way to 'cheat' but confirm whether your working is correct is to throw the answers into your equations to ensure you have formed them correctly.
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i'll definitely give it a shot tmr =)
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Originally posted by tut4nkh4m3n:
i'll definitely give it a shot tmr =)
wow what level are you?
Never seen u in homework before
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i give up..i tried from afternoon until now lol...when revealing workings/hints?
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Originally posted by dkcx:
wow what level are you?
Never seen u in homework before
a lvls. taking it this yr. prelims just over. yep, will have time in the forums for a while before i'll have to bury myself in the books all over again.
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Originally posted by qdtimes2:
i give up..i tried from afternoon until now lol...when revealing workings/hints?
It might be better to show your working etc so ultimaonline can correct your mistake and let everyone learn together.
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YAY i got it. took a while tho, found it rather tedious.
for me the challenge was converting everyth into the right molar ratio cos the mono-, di- and triprotic acid/base really make it troublesome and i had calculation errors in my first 2 attempts. after which it was merely using simultaneous equations to solve.
letting X be [H2SO4] and Y be [Na2CO3], the 2 equations i got were:
0.625X - 0.1923Y = 0
0.02933X - 0.07994Y = -0.0461yuppers. i had fun
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Congrats tut4nkh4m3n! Glad u had fun! :)
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tried it yesterday night, same approach as tut4nk4m3n, solve by simultaneous eqns. only got 0.625x - 0.1923y = 0 right.
the first eqn i tried 2 times, i think i made some errors in between...shall try again when im free.
but its solvable within 10 mins, my friend did it haha.
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Originally posted by UltimaOnline:
Congrats tut4nkh4m3n! Glad u had fun!
thanks for the question. if you've got more in the future do post them, i'll gladly give it a go =)
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sorry, but isit possible for TS to post chemistry-related-but-not-maths-related.eg-sim-eqn questions ?
really dislike it ? =.='' ?
dun like 2 mix chem with maths.
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Originally posted by yiha093:
sorry, but isit possible for TS to post chemistry-related-but-not-maths-related.eg-sim-eqn questions ?
really dislike it ? =.='' ?
dun like 2 mix chem with maths.
haha. i don't like it either. heck, i don't like a lot of things in the syllabus. but we don't really have a choice. sciences overlap with math A LOT, you should know that by now. maybe more for physics, less for biology, but they still overlap.
moreover, the question above is still more of a chemistry question than a math one. differentiate this, expand this, what's the probabilty of this, find the equation of this plane, does this function have an inverse... those would be math questions.
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------------ sorry, but isit possible for TS to post chemistry-related-but-not-maths-related.eg-sim-eqn questions ? really dislike it ? =.='' ? dun like 2 mix chem with maths. ------------- That's still possible for 'A' levels, but not for 'O' levels; because 'O' levels is way too simplified; only possible interesting (challenging) questions that can still be attempted at 'O' levels (eg. this question) are mathematics based questions.
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Originally posted by yiha093:
sorry, but isit possible for TS to post chemistry-related-but-not-maths-related.eg-sim-eqn questions ?
really dislike it ? =.='' ?
dun like 2 mix chem with maths.
I know maths is not your strong point but you still have to practice. Remember what we discuss lsat night
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Originally posted by UltimaOnline:
—-—-- sorry, but isit possible for TS to post chemistry-related-but-not-maths-related.eg-sim-eqn questions ?-
really dislike it ? =.=’’ ?
dun like 2 mix chem with maths. -—-—-That’s still possible for ‘A’ levels, but not for ‘O’ levels; because ‘O’ levels is way too simplified; only possible interesting (challenging) questions that can still be attempted at ‘O’ levels (eg. this question) are mathematics based questions.
i dun understand ?
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Originally posted by yiha093:
i dun understand ?
What he means is the O's syallabus is too simplified to give much challenging questions and the only type of questions that can offer you guys a challenge will be those that require maths.
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true to some extent. but many of the questions at 'A' lvls, challenging or not, require math.
topic such as stoichiometry, equilibria, energetics all require math. some require simple addition, others require an understand of logarithms, or how to solve simultaneous equations... these topics form a large component of the 'A' lvls syllabus.
my point is, you might not need excellent math skills to be gd in chem, but a decent grasp of the basics (addition, subtraction, multiplication, log, square...) is a must.
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Originally posted by tut4nkh4m3n:
true to some extent. but many of the questions at 'A' lvls, challenging or not, require math.
topic such as stoichiometry, equilibria, energetics all require math. some require simple addition, others require an understand of logarithms, or how to solve simultaneous equations... these topics form a large component of the 'A' lvls syllabus.
my point is, you might not need excellent math skills to be gd in chem, but a decent grasp of the basics (addition, subtraction, multiplication, log, square...) is a must.
im fine with all that. i just that i dun prefer chem with maths. ?
<3 mol thou. ~,~
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Originally posted by tut4nkh4m3n:
true to some extent. but many of the questions at 'A' lvls, challenging or not, require math.
topic such as stoichiometry, equilibria, energetics all require math. some require simple addition, others require an understand of logarithms, or how to solve simultaneous equations... these topics form a large component of the 'A' lvls syllabus.
my point is, you might not need excellent math skills to be gd in chem, but a decent grasp of the basics (addition, subtraction, multiplication, log, square...) is a must.
well...they can always slaughter you with imba organic chem questions(:
like you know, proteins and stuff. or uber hard identification questions that dont require math. but most of these stuff sec sch nvr learn. haha.
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Originally posted by yiha093:
im fine with all that. i just that i dun prefer chem with maths. ?
<3 mol thou. ~,~
In the 4 main branches of chemistry, analytical and physical chemistry are very maths base with lots of calculations especially physical chemistry which requires engineering maths knowledge.
A science student cannot runaway from maths since maths and science are linked in many ways.
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Originally posted by dkcx:
In the 4 main branches of chemistry, analytical and physical chemistry are very maths base with lots of calculations especially physical chemistry which requires engineering maths knowledge.
A science student cannot runaway from maths since maths and science are linked in many ways.
blehhh , i'll just deal with it as it comes along. yihao leii . dun play play xD
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Originally posted by absol:
well...they can always slaughter you with imba organic chem questions(:
like you know, proteins and stuff. or uber hard identification questions that dont require math. but most of these stuff sec sch nvr learn. haha.
correct. but very roughly, 'A' lvls chem paper is split into 40% organic, 40% physical, 20% inorganic.
I THINK
which shows that maybe inorganic is not so impt (haha, i hate it, boo), but the physical component is crucial, which means you need your basic math. after all, as you said, they can slaughter you with crazy elucidation/organic synthesis questions, which means you may need your physical component to back you up.