A solution of HCl is prepared by an unknown dilution of concentrated HCl. It is standardized by titrating 0.2897 grams of dried primary standard Na2CO3 with 54.76 mL acid, 0.2475 g Na2CO3 with 53.46 mL acid, and 0.2279 g Na2CO3 with 55.12 mL acid. Calculate the mean molar concentration of the HCl solution. 2. a) What is the uncertainty in the molarity in the previous problem determined by the propagation of typical uncertainties: emass = ±0.0002 g and evolume = ±0.02 mL? (You may use any one trial from Problem 2 to illustrate the propagation). b) What is the uncertainty in molarity in the previous problem if we take the uncertainty to be the standard deviation? c) For what reason(s) are the answers to B and A different? What is the cause of the difference?
1. A solution of HCl is prepared by an unknown dilution of concentrated HCl. It is standardized by titrating 0.2897 grams of dried primary standard Na2CO3 with 54.76 mL acid, 0.2475 g Na2CO3 with 53.46 mL acid, and 0.2279 g Na2CO3 with 55.12 mL acid. Calculate the mean molar concentration of the HCl solution.
2.
a) What is the uncertainty in the molarity in the previous problem determined by the propagation of typical uncertainties: emass = ±0.0002 g and evolume = ±0.02 mL? (You may use any one trial from Problem 2 to illustrate the propagation).
b) What is the uncertainty in molarity in the previous problem if we take the uncertainty to be the standard deviation?
c) For what reason(s) are the answers to B and A different? What is the cause of the difference?
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