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k0ka
2 months ago
8

Bleach contains the active ingredient NaClO. Analysis of bleach involves two sequential redox reactions: First, bleach is reacte

d in acidic solution with excess iodide anion to produce yellow-colored iodine: ClO− + 2 H+ + 2 I− → I2 + Cl− + H2O Then, to determine how much of the iodine was formed, the solution is titrated with sodium thiosulfate solution: I2 + 2 S2O32− → 2 I− + S4O62− A bit of starch is added to the titration reaction. Starch is intensely blue in the presence of I2. The solution thus turns from deep blue to colorless at the reaction equivalence point. A sample of a new cleaning product, "Joe's Famous Bleach Cleaner," with a mass of 60 g , was diluted with an acidic solution containing excess I−. A small amount of starch indicator solution was then added, turning the solution a deep bluish-purple. The solution was then titrated with 0.117 M sodium thiosulfate, Na2S2O3, containing the ion S2O32−. A volume of 43 mL of sodium thiosulfate, the titrant, was needed to turn the solution colorless. What is the percentage composition by mass of NaClO in the bleach product?
Chemistry
1 answer:
VMariaS [2.9K]2 months ago
5 0

Answer:

0.31%

Explanation:

For the chemical reaction:

I₂ + 2 S₂O₃²⁻ → 2 I⁻ + S₄O₆²⁻

0.043 L multiplied by 0.117 M of sodium thiosulfate gives 5.031x10⁻³ moles of S₂O₃²⁻

5.031x10⁻³ moles of S₂O₃²⁻ produces:

ClO⁻⁻ + 2 H⁺ + 2 I⁻ → I₂ + Cl⁻ + H2O

2.5156x10⁻³ moles of I₂ equates to moles of NaClO

2.5156x10⁻³ moles of NaClO times \frac{74,44 g}{1mol} yields 0.187 g of NaClO

Thus, the mass percentage composition is:

\frac{0,187 g of NaClO}{60 g Of Bleach} x 100 = 0.31%

I hope this helps!

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Explanation:

The rate at which gases effuse is inversely related to the square root of their molar masses.

In this case, half of the helium (1.5 L) passed through the membrane in 24 hours. Therefore, we can calculate the effusion rate of He gas as follows.

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Given that the molar mass of He is 4 g/mol and for O_{2} it is 32 g/mol.

Now,

   \frac{\text{Rate of He}}{\text{Rate of Oxygen}} = \sqrt{\frac{32}{4}

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          Rate of O_{2} = 0.022 L/hr.

This implies that 0.022 L of O_{2} gas will effuse in one hour.

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"The compound K2O2 also exists. A chemist can determine the mass of K in a sample of known mass that consists of either pure K2O
lorasvet [2795]

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Indeed, the chemist is capable of identifying the compound present in the sample.

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