Chemistry 3/4 2013 Thread

[Homer]

haha no problem, btw how are you finding chemistry so far?

[thushan]

@toucan: thanks for your help!!

@ jai: dont you need the volume??
ahh now i realise :
0.2M=0.2mol/L-
Therefore,
K+ = 0.2 x 2(as there are 2 K+ atoms)=0.04
SO4 2-= 0.2 X 1=0.02
oxygen= 0.2 X 4= 0.08


Hope that helps!!

no worries!

[teletubbies_95]

HI JAI ,
Well chem , is very interesting of course. I really like it Some parts of it are challenging , e.g IR and NMR , took me a while to understand.
But yeh. I get myself confused at the simplest things(as you can see), so i plan to improve on that .
hwboutu?

[America]

This thread is great! I'll be posting some q's up soon.

[America]

Hey guys i have a question; "To what volume of water must 10 ml of 8.0 M HCL be added in order to prepare a 0.50 M HCl solution?"
Thanks

[teletubbies_95]

Hi America!
Great question !
Remember : c1v1=c2v2
therefore,
10 x8 = 0.5 *v1
v1=160mL
Therefore add 150mL!
Hope that helps!

[Homer]

typo 160ml?

[America]

Thanks alot , just wondering have you started the book yet teletubbies?

[polar]

jai, you have to fill it up to 160mL but there's already 10mL in there, thus you need to add in another 160-10=150mL

for questions that ask you how much needs to be added (like this one), you can do:



which means you don't forget to subtract 10mL from the answer at the end

[teletubbies_95]

@america: yes!

[Homer]

aha offcourse thanks polar, also i still cant work out how to solve

for a 0.20M solution of potassium sulfate k2so4, calculate the amount in mol of:sulfate ions :/

[Homer]

btw where are you upto teletubbies?

[teletubbies_95]

Hey Jai ,
Just doing some chromotography/organic chem/
i guess the question that you are talking about ...assume 1L =volume? maybe.
it worked out for me.

[Mr Keshy]

Hey guys, what text books are we using?

[teletubbies_95]

Our school uses Heinemann !