A stock solution of copper, 1000.0 (± 0.3) mg Cu /L, is diluted tenfold by diluting 10.00 (± 0.04) mL stock to a final volume of 100.00 (± 0.05) mL. The concentration of the diluted solution, calculated using the formula Cstock.Vstock = Cdiluted.Vdiluted, is of course 100 mg Cu /L.
Cdiluted = 1000.0(±0.3) x 10.00(±0.04) / 100.00(±0.05)
Calculate the % relative uncertainty in the concentration of the 100 mg/L diluted solution. The numbers in parenthesis are absolute uncertainties. Enter your answer to two significant figures in the format 0.0E0. Do NOT include the % sign.
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Expert's answer
2020-10-14T05:47:35-0400
Milli-moles of KI=50×0.04=2Milli-equivalents of Na2S2O3 reacted with 10 mL solution=20×2.5×10−3=50×10−3 Milli-equivalent of I− left unreacted in 100 mL solution=50×10−3×10 100=0.5Milli-moles of I− reacted with CuCO3=2−0.5=1.5∵2Cu2++5I−→2CuI+I3−Milli-moles of Cu2+=5 2×1.5=0.6Weight of CuCO3=0.6×10−3×123.5=0.0741Weight % of CuO3=0.1 0.0741×100=74.1
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