× Didn't find what you were looking for? Ask a question
  
  
Top Posters
Since Sunday
11
s
6
6
a
3
1
1
1
1
1
1
1
New Topic  
Boedecjt01 Boedecjt01
wrote...
Posts: 9
Rep: 0 0
5 years ago
   I have tried using Molarity= Moles of Solute/Liters of Solution, but i cannot figure the answer out. If you can only get the first two questions, that is okay, thank you!

1) Calculate the amount of potassium ferrocyanide trihydrate [K4Fe(CN)6•3H2O] needed to prepare 250 ml of 0.025 M solution. 

2) Calculate the amount of zinc sulfate heptahydrate [ZnSO4•7H2O] needed to prepare 250 ml of 0.050 M solution. 

3) Assuming that the actual molarities of your stock solutions are equal to the target molarities given above, calculate what titration volume of zinc sulfate would be expected for titrating  a 25.00 ml aliquot of the ferrocyanide solution for each of the five  possible reactions presented below:

   K4Fe(CN)6(aq)  +  ZnSO4(aq) -----> K2ZnFe(CN)6(s)  +  K2SO4(aq)

   K4Fe(CN)6(aq)  +  2 ZnSO4(aq) ----> Zn2Fe(CN)6(s)  +  2 K2SO4(aq)

   2 K4Fe(CN)6(aq)  +  ZnSO4(aq) ----> K6Zn[Fe(CN)6]2(s)  +  K2SO4(aq)

   2 K4Fe(CN)6(aq)  +  3 ZnSO4(aq) ----> K2Zn3[Fe(CN)6]2(s)  +  3 K2SO4(aq)

   3 K4Fe(CN)6(aq)  +  2 ZnSO4(aq) ----> K8Zn2[Fe(CN)6]3(s)  +  2 K2SO4(aq)
Read 917 times
11 Replies

Related Topics

Replies
wrote...
Educator
5 years ago
For #1 and #2, see if this helps before I continue
Attached file
Thumbnail(s):
You must login or register to gain access to this attachment.
wrote...
5 years ago
Where did the 3 come from on the outside of the bracket in problem 1?
wrote...
Educator
5 years ago
I thought it contained it... opps.
wrote...
5 years ago
The MWt of [K4Fe(CN)6•3H2O] (C6H6FeK3N6O3) = 383.3 g

250 mL of 0.025 M K4Fe(CN)6•3H2O contains (250/1000)×0.025 = 6.25×10^-3 mole

Hence amount needed = (6.25×10^-3)×383.3 = 2.40 g (should only be 2 sig figs)
Source https://biology-forums.com/index.php?action=downloads;sa=view;down=14860
wrote...
5 years ago
I have tried using Molarity= Moles of Solute/Liters of Solution, but i cannot figure the answer out. I have the first two, but the third question is confusing.
wrote...
Educator
5 years ago
I'm unsure how to tackle it too Frowning Face
wrote...
3 years ago
Thank you
wrote...
2 months ago
.
SMR
wrote...
A month ago
thank you
wrote...
A month ago
3. Molarity of ZnSO4. 7H2O = 0.050 M

Volume = 250 mL = 0.250 L

Moles of ZnSO4. 7H2O = Molarity * Volume = 0.050 M * 0.250 L = 0.0125 moles

Molar mass of ZnSO4. 7H2O = 287.5496 g/mol

Mass of  ZnSO4. 7H2O = Moles * Molar mass = 0.0125 moles * 287.5496 g/mol = 3.59 g
wrote...
A month ago
.
New Topic      
Explore
Post your homework questions and get free online help from our incredible volunteers
  144 People Browsing
 256 Signed Up Today
Your Opinion
Which 'study break' activity do you find most distracting?
Votes: 278

Previous poll results: What's your favorite coffee beverage?
Related Images
 383
 81