I\'m posting these all together because they are all very similar. 1. How many h

Question

I'm posting these all together because they are all very similar.

1. How many hours are required for 0.200 mol electrons to flow through a cicuit if the current is 2.00A

A. 2.68

B. 160.8

C. 5.37

D. None of the above

Answer is A. 2.68. Please show work/explain.

2. How many hours are required for oxidizing 0.200 mol of Cu Cu2+ if the current is 2.00A

A. 2.68

B. 160.8

C. 5.36

D. 1.34

Answer is C. 5.36. Please show work/explain.

3. How many hours are require for reducing 0.150 mmol of Cu2- to Cu if the current is 0.350 mA

A. 5.36

B. 11.5

C. 53.6

D. 23.0

Please show work/explain

please state clearlythe formiula you used also. thank you.

Explanation / Answer

1) t = Q / I

= 0.2*(6.023*10^23) *(1.6*10^-19) / 2 = 2.68 hrs

6.023*10^23 electrons are present in 1 mole

1.6*10^-19 C is charge on 1 electron

2) when 0.2 mol of Cu+2 is present it simply means 0.2*2 = 0.4 moles of charge

so the time simply becomes twice of the time obtained in 1)

so t = 2*2.68 = 5.36 hrs

3) t = (0.15*10^-3) * (6.023*10^23)* (2*1.6*10^-19) / 0.35*10^-3

= 23 hrs

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