Stoichiometry of 2step process

Shing Hin

2012-02-19 12:52 am

Consider the following two-step reaction sequence.

2NaCl + 2H2O
圖片參考：https://lewis.chem.sfu.ca/res/sfu/batchelo/CAPA5stuff/gifGallery/rarrow.gif
2NaOH + H2 + Cl2
2Fe + 3Cl2
圖片參考：https://lewis.chem.sfu.ca/res/sfu/batchelo/CAPA5stuff/gifGallery/rarrow.gif
2FeCl3

Assuming that all the chlorine generated in the first step is consumed in the second step, what mass of NaCl is needed in the first step to produce 13.2 g of FeCl3 in the second step?

回答 (1)

sioieng

2012-02-19 7:02 am

✔ 最佳答案

Method 1 :
2Fe + 3Cl2 → 2FeCl3
No. of moles of FeCl3 formed = 13.2/(55.8 + 35.5x3) = 0.08133 mol
No. of moles of Cl2 = 0.08133 x (3/2) = 0.1220 mol

2NaCl + 2H2O → 2NaOH + H2 + Cl2
No. of moles of Cl2 formed = 0.1220 mol
No. of moles of NaCl used = 0.1220 x 2 = 0.2440 mol
Mass of NaCl used = 0.2440 x (23 + 35.5) = 14.27g

Method 2 :
6NaCl + ... → 3Cl2 + ... → 2FeCl3
No. of moles of FeCl3 formed = 13.2/(55.8 + 35.5x3) = 0.08133 mol
No. of moles of NaCl = 0.08133 x (6/2) = 0.2440
Mass of NaCl used = 0.2440 x (23 + 35.5) = 14.27g

參考: sioieng

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