Question

Preparation of the 0.100 M Na,3,0, solution. What mass of Na S,0,5H0 is needed to make 250 mL of 0.100 M Na,s,o, solution? Show your work for this calculation in the space below. (Note: you need to include the 5 H,O's when you calculate the molar mass) 2) Mass of Na S,0, 51,0 needed for 250.00 mL 0.100 M Na S,O, solution. Standardization of the Na S,0, solution. Unlike the KIO, solution, the Na S,O, solution molarity will not be exactly 0.100 M because the substance weighed out is never 100% pure Na S,0, 51,0. This means we need to standardize the solution to find its exact concentration. We do this using a titration, similar to how we determined the concentration of an unknown HCl solution in a previous lab. This titration is a little more complex though. Following the information in the prelab discussion and the chemical equations given, calculate the concentration of your Na S,O, solution Note that it will be close to but not exactly the nominal value of 0.100 M. Show your work in the space below. Make sure you write chemical formulas and units in all calculations. You will not get full points unless you do this. Here is the data from the virtual experiment: 13.96 mL of your Na S,0solution was required to react with 25.00 ml of your 0.0100 M KIO, solution.

Answer 1

- ② Volume of Nas S. Og solution - 250 mL = 0.25L Molarity of the solution = 0.100M ". Moles of Naz Sa Og • 560 = Molarity & Volume = (0-100 x0.25) = 0.025 Molor mass of Na₂S₂O₂ . 540 = 248.18 418 . Mass of Naz S₂ Oz 5H₂0 needed - (0.025 x 248-18419 = 6.2g KIO, + 5KI + 6HCl → 31, +6 kcl + 3H0 IL + 2Na, 9,03 → 2NaI + Na, S406 : 29,05 Cam + I I cogs 2 Ratio: 2 : 1 2 Volume of KIO₂ solution = 25 mL = 0.025 L Concentration of KIO solution = 0.01M Moles of KIO₃ = Molarity & Volume = (0.01 x 0.025) = 0.00025 . Moles of Iz formed = (3x0.00025) = 0.00075 . Moles of Naz S20₃ reacted = (0.000 75 x2) = 0.0015 Volume of NazS, O solution = 13.96 mL = 0.01396L . Concentration of Naz ₃ solution = Moles + S4 6 (age - 0.0015 M - Volume = 10.107 M-