Calculation Questions! (1 Viewer)

[zhertec]

0.22

Damn you beat me to it lol

 

[zhertec]

Tbh I'm more scared of the responses than calculations atm, they always seem to fk me over.

 

[fatima96]

Tbh I'm more scared of the responses than calculations atm, they always seem to fk me over.

Tbh I prefer a paper with calculations : theory with a ratio of 9:1 lmao

 

[tommoo]

Simple titration - http://imgur.com/eKfo5mE

Go

 

[tommoo]

Mass of sulfur = 24% of 1g
thus m(S) = 0.24 gram.
n(S) = 0.24/32.07 = 0.007483.......mol

n(S) = n(SO42-)

m(SO42-) = n x M
= 0.0074836 x (32.07 + 16 + 16 + 16 + 16)
= 0.7189....g

Thus, precentage = 0.718 g sulfate / 1 g fertiliser = 72%

Mind explaining why/where/how you get the sulfate to continue the equation? Is the fertiliser as a whole sulfate? I understand all the working but am just trying to figure out where the sulfate comes from.

 

[SuchSmallHands]

Mind explaining why/where/how you get the sulfate right to continue the equation? I understand all the working but am just trying to figure out where the sulfate comes from.

n(sulfur) = n(sulfate)

 

[tommoo]

n(sulfur) = n(sulfate)

Where does the sulfate come from in the question? Is that assumed knowledge?

 

[SuchSmallHands]

Where does the sulfate come from in the question? Is that assumed knowledge?

Well if you've got barium sulfate forming in the precipitation reaction there's going to be sulfate in the fertiliser, yes. But the question says there's sulfur in the fertiliser, and that would be in the form of some kind of sulfate (probably K2SO4). That's just assumed knowledge from having done the course.

 

[tommoo]

Well if you've got barium sulfate forming in the precipitation reaction there's going to be sulfate in the fertiliser, yes. But the question says there's sulfur in the fertiliser, and that would be in the form of some kind of sulfate (probably K2SO4). That's just assumed knowledge from having done the course.

Thanks.

Will fertiliser questions such as this always have a 1:1 ratio? Would you mind writing the balanced equation it forms?

 

[fatima96]

Mind explaining why/where/how you get the sulfate to continue the equation? Is the fertiliser as a whole sulfate? I understand all the working but am just trying to figure out where the sulfate comes from.

The sulfur in the fertiliser is part of the SO42- (sulfate)
So thus, the number of moles of sulfur = to number of moles of sulfate
Fertiliser as a whole is not sulfate, but it does contain sulfate. It is common knowledge that fertiliser contains sulfate
Are you doing HSC this year for chem?

 

[tommoo]

The sulfur in the fertiliser is part of the SO42- (sulfate)
So thus, the number of moles of sulfur = to number of moles of sulfate
Fertiliser as a whole is not sulfate, but it does contain sulfate. It is common knowledge that fertiliser contains sulfate
Are you doing HSC this year for chem?

No, i'm doing it next year.

Thanks though!

 

[faisalabdul16]

No, i'm doing it next year.

Thanks though!

Then why you so worried about this stuff now? You'll learn it next year

 

[fatima96]

No, i'm doing it next year.

Thanks though!

No worries, you'll get it when you do module 3.
All the best with year 12.

 

[ushnakhalid]

Tbh I prefer a paper with calculations : theory with a ratio of 9:1 lmao

hahahaha of course you do miss band 6 in accelerated math

 

[tommoo]

Then why you so worried about this stuff now? You'll learn it next year

Because I prefer to put in my own effort than depend on my teachers. If I know the knowledge before doing the module I will breeze through it.

No worries, you'll get it when you do module 3.
All the best with year 12.

Thank you.

 

[faisalabdul16]

Because I prefer to put in my own effort than depend on my teachers. If I know the knowledge before doing the module I will breeze through it.



Thank you.

If you learn by yourself there is most likely going to be holes in your information since you do not know what is important or not. And then when a teacher explains you're most likely going to be like "I already know this so ill do something else during class" and you miss out on some detail which you may have disregarded.

 

[tommoo]

If you learn by yourself there is most likely going to be holes in your information since you do not know what is important or not. And then when a teacher explains you're most likely going to be like "I already know this so ill do something else during class" and you miss out on some detail which you may have disregarded.

Learning independently has always been my preferred method, along with information from teachers reinforcing the dendrites that i have previously built. I learn directly off syllabus dot points and cross reference conquering chemistry, chemistry in context and the HSC guide to chemistry. I always make sure to listen in class .

Good luck in your exam tomorow!

 

[riri109360]

I actually enjoy studying chemistry!
Challenging calculations are good, have you done some back titrations?
They are pretty tough

 

[Chris100]

rofl i just read through this thread
I hope noone used this thread to gain some knowledge about chemistry for the exam or especially you hsc 2016 guy
This is ridiculous, you have to use a chemical equation with known mole ratios to make any sort of deduction about the molar ratio between 2 compounds or an element and compound or whatever combo
you cant just go oh yes, sulfur, oh sulfate ions has sulfur, therefore n (sulfur)= n (sulfate ions) wtf AHHAHAHA

 

[SuchSmallHands]

rofl i just read through this thread
I hope noone used this thread to gain some knowledge about chemistry for the exam or especially you hsc 2016 guy
This is ridiculous, you have to use a chemical equation with known mole ratios to make any sort of deduction about the molar ratio between 2 compounds or an element and compound or whatever combo
you cant just go oh yes, sulfur, oh sulfate ions has sulfur, therefore n (sulfur)= n (sulfate ions) wtf AHHAHAHA

Loooolllll, stoich ratio sulfur to sulfate 1:1, obviously n (sulfur) = n (sulfate). If anyone didn't get that the night before the HSC and I had to type all that out than it was never going to help them anyway. I got the right answer, so laugh all you like.