1) Find mass and moles of carbon
"n(C)= \\frac{9.62\\times 10^{-3}}{44.01} =0.000219 moles"
"m(C) =n\\times M = 0.000219\\times 12.01 = 0.00263 g =2.63 mg"
2) Find mass and moles of hydrogen
"n(H) = n(H_2O)\\times 2 =\\frac{3.94\\times10^{-3}}{18.02} \\times 2 = 0.000437 moles"
"m(H) = n\\times M = 0.000437\\times 1 = 0.437mg"
3) Find mass percent of chlorine in a sample
a) find mass of chlorine if silver nitrate:
"n(AgCl )= \\frac{m}{M} = \\frac{13.49\\times 10^{-3}}{143.32} = 0.0000941 mol"
"n(Cl) = n(AgCl) = 0.0000941 mol"
"m(Cl) = 0.0000941\\times35.45 = 0.00334 g = 3.34 mg"
b) find mass percent of chlorine in silver nitrate
"mass\\% (Cl)= \\frac{3.34}{5.32} =0.627"
4) Find mass and moles of chlorine in the first sample
"m(Cl) = m_{sample}\\times mass\\%(Cl) = 8.23\\times 0.627 = 5.16 mg"
"n(Cl) = \\frac{m}{M} = \\frac{5.16\\times10^{-3}}{35.45} = 0.000146 mol"
5) check up if there is an oxygen in a sample:
"8.23 = m(O) + m(C) + m(H) + m(Cl)"
"8.23 = m(O) +2.63 + 0.437 + 5.16"
"m(O) = 0.003 mg" (negligible)
6) find mole ratio
"n(C):n(H):n(Cl) = 0.000219:0.000438:0.000146 \n= 1.5:3:1 = 3:6:2"
The formula is "C_3H_6Cl_2"
7) Percent composition
mass percent "\\% (c) = \\frac{2.63}{8.23}\\times 100\\% = 32.0\\%"
mass percent "\\% (H)= \\frac{0.437}{8.23} \\times 100\\% = 5.31 \\%"
mass percent "\\% =\\frac{5.16}{8.23} \\times 100\\% = 62.7\\%"
Comments
Dear Heidi, Questions in this section are answered for free. We can't fulfill them all and there is no guarantee of answering certain question but we are doing our best. And if answer is published it means it was attentively checked by experts. You can try it yourself by publishing your question. Although if you have serious assignment that requires large amount of work and hence cannot be done for free you can submit it as assignment and our experts will surely assist you.
Sorry, I meant halogen analysis.
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