1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Wittaler [7]
3 years ago
8

In the redox persulfate-iodide experiment, a 100 mL reaction mixture is prepared for one of the runs as follows. 0.200 M KI 20 m

L 0.200 M KNO3 15 mL 0.25% starch 5 mL 0.01 M Na2S2O3 10 mL 0.1 M EDTA 1 drop water to make 65 mL 0.200 M (NH4)2S2O8 35 mL a. How many moles of S2O32- would react when the solution turns dark blue? b. How many moles of S2O82- would react when the solution turns dark blue? c. What would be the initial rate of reaction if this reaction mixture took 200 seconds to turn dark blue?
Chemistry
1 answer:
grigory [225]3 years ago
4 0

Answer:

a) The number of moles of thiosulphate ( S₂O₃2-) that reacted to turn the solution dark blue will be 0.0001M.

b) The number of moles of  S₂O₈2- that would react to produce the blue color will be 0.00005 M.

c) rate = 2.5 x 10-6M/L/s

Explanation:

a)

The reactions taking place in this experiment are represented by the ionic equations,

S₂O₈ 2- + 2I- ----------> 2SO₄2- + I₂ --------------------(1)

2 S₂O₃2- + I₂ -----------> S₄O₆ +2 I-  -------------------(2)

The persulphate ions react with the iodide ions to produce free iodine which is in turn reduced by the thiosulphate ions to produce iodide ions again. This reaction proceeds till all the thiosulphate ions are used up. Therefore the rate of the reaction will be the rate at which iodine is formed and used up.

When there is free iodine the reaction mixture,  the solution gives a dark blue coloration. This happens when all the thiosulphate ions are used up.

The volume of sodium thiosulphate ( Na₂S₂O3) solution added to the reaction vessel = 10ml

Molarity of sodium thiosulphate ( Na₂S₂O3) solution = 0.01M

Number of moles of ( Na2S2O3) = 0.01ml x 10M /1000ml = 0.0001M (molarity x volume in L)

The number of moles of thiosulphate reacted will be equal to the number of moles taken since the reaction proceeds till all the thiosulphate is consumed.

Hence, the number of moles of thiosulphate ( S₂O₃2-) that reacted to turn the solution dark blue will be 0.0001M.

b)

To calculate S₂O₈ 2-

The permanent blue color is produced once all the thiosulphate ions are used up and persulphate reacts with iodide ions to produce iodine, so, the number of moles of persulphate ions will be equal to the number of moles of iodine formed

According to the stoichiometry of equation 1.

1 mole of  S₂O₈ 2-produces 1 mole of iodine.

According to the stoichiometry of equation 2,

1mole of iodine produced consumes 2 moles of  S₂O₃2-

The number of moles of  S₂O₃2- taken = 0.0001M.

2 moles of   S₂O₃2- is equivalent to 1 mole I₂

therefore

0.0001 mole of   S₂O₃2- = 0.0001/2 = 0.00005M of I₂

Since stoichimetrically,

1 mole of  S₂O₈2- is equivalent to 1 mole I2, the number of moles of  S₂O₈2- that would react to produce the blue color will be 0.00005 M.

c)

The initial reaction rate is given by

rate =change in concentration of persulphate ion [S₂O₈2-] / time

rate = change in Concentraion of I₂ / t

since initial concentration of I₂ = 0.

rate = Concentraion of I₂/ t

The concentration of I₂ = number of moles of iodine / total volume of solution in L

= 0.00005M/ 0.1L = 0.0005M/L (Volume of the solution = 100ml = 0.1L)

rate = Concentraion of I₂ / t

= 0.0005 /200s

rate = 2.5 x 10-6M/L/s

You might be interested in
Ben observes how quickly some dry wood is burning in a campfire. which term best relates to ben's observation?
Katyanochek1 [597]
I think this the the list of choices relating to the above question.
reaction rate 
<span>activation energy </span>
<span>collision theory </span>
<span>spontaneous reaction
</span>
The term that best relate to ben's observation is REACTION RATE.

Reaction rate is defined as the speed at which the chemical reaction proceeds. It either is the amount of concentration of a product in a given unit of time or the concentration of the reactant that is being consumed in a unit of time.
7 0
3 years ago
Read 2 more answers
What is the molar mass of PCL3
antiseptic1488 [7]
The molar mass for PCL3 is 137.33 g/mol
8 0
3 years ago
Do ghosts exists ?? ...​
Nesterboy [21]

Answer:

no

Explanation:

it is human imagination about scary things that brought about ghost

5 0
2 years ago
Plz help! NO FAKE ANSWERS PLEASE
aleksklad [387]

Answer:

postion emmsion

Alpha decaya

gamma decay

beta decay

in order

Explanation:

and there is 100% of humans dieing becasue of atoms decays which is sad and also answers the question does life have meeain and no we are all going to die anyways

7 0
2 years ago
Read 2 more answers
Some common substances used in the laboratory are listed in the table. the chemical formulas of the substances are also listed b
Helga [31]
Its 5 i think

but dont take my word on it

7 0
3 years ago
Other questions:
  • For some hypothetical metal the equilibrium number of vacancies at 750°C is 2.8 × 1024 m−3. If the density and atomic weight of
    14·1 answer
  • Use the unbalanced equation NH3 + O2 = NO + H2O, what is the mole ratio between NH3 and NO
    7·2 answers
  • What is the proper name for this fomula BaCl 2
    12·2 answers
  • Which diagram shows a pair of electrons that have opposite spins?<br> OT<br> 11<br> 11<br> 个个
    13·2 answers
  • A mothball, composed of naphthalene (c10h8), has a mass of 1.64 g . part a how many naphthalene molecules does it contain?
    9·1 answer
  • In what way does the shape of a molecule affect how the molecule is
    7·1 answer
  • What is a small-ball shaped organelle that helps the cell break down nutrients and old cell parts.
    5·1 answer
  • H2 + I2 &lt;=&gt; 2HI + 3 kcal
    9·2 answers
  • Complete the nuclear reaction.*
    6·1 answer
  • Which best describes the source of radiation heat
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!