There is a question on my science study guide that i could not find the answer to. Can anyone help? Thanks in advance?

[匿名]

2016-05-30 8:07 am

The question goes as follows:
Balance the redox reaction:
F^+3 + Sn^+2 --- Fe^+2 + Sn^+4

And:
determine the mass percent of Fe^+3 in a 0.7450 g sample of iron ore, if 22.40 mL of 0.1000 M (I think moles?) stannous cloride, SnCl2, solution is required to completely react with the Fe^+3 present in the ore sample.
Thanks for the help

回答 (2)

不用客氣

2016-05-30 8:21 am

✔ 最佳答案

Reduction half equation : Fe³⁺ + e⁻ → Fe²⁺ ...... [red]
Oxidation half equation : Sn²⁺ → Sn⁴⁺ + 2e⁻ ...... [oxid]

[red] × 2 + [oxid], and cancel 2e⁻ on the both sides. The balanced equation for the overall reaction is :
2Fe³⁺ + Sn²⁺ → 2Fe²⁺ + Sn⁴⁺

====
Number of moles of SnCl₂ reacted = (0.1000 mol/L) × (22.40/1000 L) = 0.002240 mol

1 mole of SnCl₂ contains 1 mole of Sn²⁺.
Number of moles of Sn²⁺ reacted = 0.002240 mol

According to the equation above, mole ratio Fe³⁺ : Sn²⁺ = 2 : 1
Number of moles of Fe³⁺ reacted = (0.002240 mol) × 2 = 0.004480 mol

Molar mass of Fe = 55.85 g/mol
Mass of Fe³⁺ reacted = (55.85 g/mol) × (0.004480 mol) = 0.2502 g

Mass percent of Fe³⁺ = (0.2502/0.7450) × 100% = 33.58%

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[匿名]

2016-05-30 8:09 am

you are STUPID

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