urgent help with question/working pls (1 Viewer)

[t234]

What would be the working out for part (b)???
There's no solutions to this paper - Abbotsleigh 2021 on THSC

 

[t234]

can someone pls check if this is right:

3.78 x 10^-5 mol/L is the diluted
3.78 x 10^-4 mol/L is the undiluted
Then since there's 50mL, 3.78 x 10^-4 x (50 x 10^-3) moles
=0.0000189 moles

0.0000189 mol x 500.158 g/mol = 0.0094529 g

So, 0.0094529/5
= 0.189%

 

[lettucechamber]

can someone pls check if this is right:

3.78 x 10^-5 mol/L is the diluted
3.78 x 10^-4 mol/L is the undiluted
Then since there's 50mL, 3.78 x 10^-4 x (50 x 10^-3) moles
=0.0000189 moles

0.0000189 mol x 500.158 g/mol = 0.0094529 g

So, 0.0094529/5
= 0.189%

this is not the right forum to ask for help. stop acting so entitled. if u need urgent help, get a tutor.

 

[C2H6O]

can someone pls check if this is right:

3.78 x 10^-5 mol/L is the diluted
3.78 x 10^-4 mol/L is the undiluted
Then since there's 50mL, 3.78 x 10^-4 x (50 x 10^-3) moles
=0.0000189 moles

0.0000189 mol x 500.158 g/mol = 0.0094529 g

So, 0.0094529/5
= 0.189%

I don't see any errors here
I did a different method and got the same answer

Also idk what that guy is yapping about this is a study forum

 

[t234]

I don't see any errors here
I did a different method and got the same answer

Also idk what that guy is yapping about this is a study forum

thank youu
can i see your method if you dont mind?

 

[C2H6O]

thank youu
can i see your method if you dont mind?

3.78 x 10^-5 mol/L is the concentration of 100ml
in the 100 ml there is 3.78 x 10^-6 mol
there's 50ml total, so you could fill 5 volumetric flasks each with 3.78 x 10^-6 mol of PFOS in it
total 3.78 x 10^-6 mol x 5 = 0.0000189 mol
m = 0.0000189 mol x 500.158 = 0.00945
% = 0.00945/5 = 0.189%

 

[t234]

thanks !