Analysis of Bleach
1. use stoich and the balanced equations to calculate mol thiosulfate from mol ClO.
2. find the average volume of titrant from the three trials (if one trial is way off throw out that data).
3. take this volume in liters and use the stoich of the equation to calculate mol NaClO, then divide by 25.0 mL to get its molarity
4. Use M1V1 = M2V2
5. Density of commericial bleach is 1.08 g/mL. Take the molarity calculated in #4 and convert this to grams NaClO using the density to find the grams solution. Use the molar mass to find grams NaClO. Use these two pieces of data to calculate the % by mass of NaClO.
6. Compare your %NaClO to that on the label of the bleach bottle (6.00% for both Target and Clorox) to get % error (this assumes the label is correct).
7. Calcuate the average deviation of volume from your three trials. To do this find the absolute value difference between each trial mL and the average volume (calculated in #2), then average these three values to get average deviation in mL. Find the relative deviation by taking the average deviation (just calculated) and dividing by the average mL (from #2) then times 100%. This gives the relative deviation value in percent.
8. bring your calculated %NaClO to class where we will compare the groups' data and decide if Target = Clorox.

King Philip Regional School District
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