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Topic: Analytical Chem Help me :P  (Read 1912 times)

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Offline James1019

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Analytical Chem Help me :P
« on: January 18, 2020, 08:40:30 AM »
Hello guys,im new here so welcome me :P. I need your help in those 2 ex.
13. A silver nitrate solution contains 14.77 g of primary standard AgNO 3 in
1.00 L. What volume of this solution will be needed to react with:
(a) 0.2631 g of NaCl? M w (NaCl) = 58.44 g mol -1 , M w (AgNO 3 ) = 169.87 g mol

23. The concentration of hydrogen peroxide in an antiseptic solution was
determined by titration with 0.0200 M potassium permanganate solution.
20.00 mL of the peroxide solution was diluted to 250.0 mL. 20.00 mL
aliquots of the diluted solution were acidified and titrated with the potassium
permanganate solution. An average titre of 18.93 mL was required.
Calculate the concentration of the hydrogen peroxide in the antiseptic
solution
2MnO 4 – (aq) + 5H 2 O 2 (aq) + 6H + (aq) 2Mn 2+ (aq) + 8H 2 O(l) + 5O 2 (g)

thanks

Offline chenbeier

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Re: Analytical Chem Help me :P
« Reply #1 on: January 18, 2020, 08:46:45 AM »
Show first your own work
Calculate the Mole of NaCl, write chemical reaction between silver nitrate and sodiumchloride.
How much mole silver nitrate  does it correspond. Convert this to the mass and then calculate the volume of the given solution.

Second question. Calculate the mole of the used permanganate solution. According the chemical equation how much peroxide correspond to it. This amount was in 20 ml. This calculate to 250 ml and correspond to the 20 ml sample.
« Last Edit: January 18, 2020, 08:56:47 AM by chenbeier »

Offline James1019

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Re: Analytical Chem Help me :P
« Reply #2 on: January 18, 2020, 08:55:19 AM »
Show first your own work

i found  the concentration at e.q. of AgNO3 that is 0,0825 and the NaCl 0.0045 i dont know what to do and in the second exercise im completely lost

****didn't see tha you write how to move on those excersises ,i saw only this <<Show first your own work>> thanks.

Offline AWK

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Re: Analytical Chem Help me :P
« Reply #3 on: January 18, 2020, 09:02:03 AM »
Now you need a balanced reaction.
AWK

Offline James1019

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Re: Analytical Chem Help me :P
« Reply #4 on: January 18, 2020, 09:13:07 AM »
Show first your own work
Calculate the Mole of NaCl, write chemical reaction between silver nitrate and sodiumchloride.
How much mole silver nitrate  does it correspond. Convert this to the mass and then calculate the volume of the given solution.

Second question. Calculate the mole of the used permanganate solution. According the chemical equation how much peroxide correspond to it. This amount was in 20 ml. This calculate to 250 ml and correspond to the 20 ml sample.

according to my calculations the new moles are n'=0,0824->m'=13,99,with what formula im going to find the volume?

Offline AWK

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Re: Analytical Chem Help me :P
« Reply #5 on: January 18, 2020, 09:18:21 AM »
Check this number:
Quote
0.0825
balance reaction
AWK

Offline James1019

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Re: Analytical Chem Help me :P
« Reply #6 on: January 18, 2020, 09:26:08 AM »
Check this number:
Quote
0.0825
balance reaction

Ok,but what do you mean with that, i cant understand :/

Offline chenbeier

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Re: Analytical Chem Help me :P
« Reply #7 on: January 18, 2020, 09:28:51 AM »
Where did you get this number.
The second is what is the balanced chemical equation between sodiumchloride and silver nitrate.
Calculate the mole of NaCl and look how much mole Silver nitrate you need.

Offline shchavel

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Re: Analytical Chem Help me :P
« Reply #8 on: January 24, 2020, 12:03:19 PM »
Why this quenstion is in analytical chem topic? >:(

Offline chenbeier

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Re: Analytical Chem Help me :P
« Reply #9 on: January 27, 2020, 01:53:42 PM »
Because Chloride can be determined by silver ions and vise versa. Mohr, Vollard, etc.

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