hardest chem questions (2 Viewers)

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whats the hardest hsc chem questions u've seen and post them up cos judging from all the exams this year itll be pretty safe to say that they'll put some fucked up questions in there.

most difficult one i've seen (not really difficult, just impossible to know if u havent seen it before)

draw a lewis dot diagram for carbon monoxide.
 
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b3kh1t

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whats the hardest hsc chem questions u've seen and post them up cos judging from all the exams this year itll be pretty safe to say that they'll put some fucked up questions in there.

most difficult on i've seen (not really difficult, just impossible to know if u havent seen it before)

draw a lewis dot diagram for carbon monoxide.
it has 2 normal covalent bonds then the oxygen gives 2 electrons to form a coordinate covalent bond, not sure how you want me to draw it on this and I'd say know validity and reliability well :D
 

b3kh1t

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hahaha um define validity and reliability, happy lol
 

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ground based- dobson ozone spectrophotometer, uses spectrometry to record the varying uv absorbtion strengths.

airborne- TOMS or total ozone map spectrophotometer, uses several satellites to map out an ozone concentration map
 

lolcakes52

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Aiight well what are exapmles of both ground and airborne instruments used to measure ozone and how is it measured??
uv spectrophotometer can be pointed both upwards(on the ground) and downwards(on a satellite, in the air), in the form of a total ozone mapping spectrophotometer. Ozone density is measured in dobson units, a measure of density where 1DU corresponds to 0.01mm of ozone.

A hard question is something like justify the use of microscopic membrane filters in the purification of water and where is this inappropriate? $10 says a 5-7 mark question on filtration pops up this year.
 
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uv spectrophotometer can be pointed both upwards(on the ground) and downwards(on a satellite, in the air), in the form of a total ozone mapping spectrophotometer. Ozone density is measured in dobson units, a measure of density where 1DU corresponds to 0.01mm of ozone.

A hard question is something like justify the use of microscopic membrane filters in the purification of water and where is this inappropriate? $10 says a 5-7 mark question on filtration pops up this year.
how is this hard?
 

lolcakes52

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Because you have to establish when microscopic membrane filters are useful eg when the flocculant doesn't work adequately, then you have to discuss how it is useful as a partial replacement of sanitisation. The price needs to be considered, along with the fact that certain chemicals can destroy the filter, meaning that it has to be used in conjunction with other specific techniques.
 

lolcakes52

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Rather than knowledge based? Chemistry is mainly knowledge based, aside from the calculations but there are only so many questions which can be asked based on calculations.
 

b3kh1t

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when i mean hard i mean skill-based hard
dude seriously get over yourself, this is what they found hard or something useful they may come tomorrow, why don't you give us a "hard" chem question
 

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dude seriously get over yourself, this is what they found hard or something useful they may come tomorrow, why don't you give us a "hard" chem question
i dont have hard questions which is why i want i'm asking for them, and that stuff is just relying on memory and rote learning, theres nothing hard about that other than the effort of memorising the shit.
 

lolcakes52

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All of the chemistry is done from memory, its not like you can walk in there and teach yourself. Good luck.
 

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i dont think you ppl understand the point of this thread

this thread isnt here to help you with your chemistry concepts and questions, theres already a thread for that. this thread is for the hardest chem questions u've seen
 

DNETTZ

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i dont think you ppl understand the point of this thread

this thread isnt here to help you with your chemistry concepts and questions, theres already a thread for that. this thread is for the hardest chem questions u've seen
people did and you told them that it wasnt hard
 

nichorowitz

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ground based- dobson ozone spectrophotometer, uses spectrometry to record the varying uv absorbtion strengths.

airborne- TOMS or total ozone map spectrophotometer, uses several satellites to map out an ozone concentration map
TOMS was replaced by OMI in 2000.
haha
 

Squishxmishyx

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The following diagram shows the steps taken in an experiment to find the percentage of pure calcium carbonate in a sample of limestone. The impurities in the limestone are solids that do not react with either the HCL or NaOH.
-Weigh out 10g of limestone
-Add 100mL of 2molL Hydrochloric acid to the limestone
-Allow all reaction to cease
-Titrate the reaction mixture against 1molL Sodium Hydroxide solution
-Result 40mL of NaOH is needed to nautralise.

1) Calculate the amount of HCl left after the reaction of the Calcium Carbonate with the acid
2) Calculate the amount of HCl that reacted with the Calcium Carbonate in the limestone
3) What is the percentage of pure Calcium Carbonate in the limestone?

Lol tit rate
 
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