Weight percent of hypochlorite in bleach

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To determine the weight percent of hypochlorite in a bleach sample, the process involves diluting 5 mL of bleach to 100 mL and titrating 30.00 mL of this solution with 29.65 mL of a 0.1034 M thiosulfate solution. The reactions include hypochlorite reacting with iodide to produce iodine, followed by titration of iodine with thiosulfate. Calculating the moles of thiosulfate allows for back-calculation to find the moles of hypochlorite present. The final step is to convert these moles into mass and then calculate the weight percent based on the original bleach solution. Understanding whether the weight percent is based on weight/volume or weight/weight is crucial for accurate results.
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Homework Statement


If 5 mL of a bleach sample is diluted to 100 mL and then 30.00 mL of the dilute solution is titrated with 29.65 mL of a 0.1034 M solution of thiosulfate what is the weight percent of hypochlorite in the 5 mL of bleach?


Homework Equations


OCl−(aq) + 2I−(aq) → I2(aq) + Cl−(aq)
First hypochlorite is reacted with idiode

then we titrate the I2 with thiosulfate
I2(aq) + S2O32−(aq) →I−(aq) + S4O62−(aq)

The Attempt at a Solution



I started by finding moles of thiosulfate and related to I2 and relate back to the hypochlorite OCl- then I used those moles to mass of the OCl- and then after that I'm not sure what to do.
 
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Knowing moles can you tell us how much it (NaOCl) might weigh?

Are you asked for a weight percent based on volume (weight/volume) or based on weight (weight/weight) of the original bleach solution?
 
chemisttree said:
Knowing moles can you tell us how much it (NaOCl) might weigh?

Are you asked for a weight percent based on volume (weight/volume) or based on weight (weight/weight) of the original bleach solution?

Based on volume, per 100 mL
 
Have you tried to answer the first question chemistree asked?
 
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Make sure all of your reactions are balanced. Start with finding the moles of thiosulfate and calculate each step backwards until you reach moles of hypochlorite. Think of the original problem description as requiring a sequence of problems to solve.
 
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