<span>Answer:
The half-reaction is as followed:
Cr2O72â’(aq) + 14H+ + 6e⒠→ 2Cr3+(aq) + 7H2O
From the half-reaction, you can retrieve the following information:
1 mole of potassium dichromate =6 moles of e^-
6 moles of e^-=2 moles of Cr
You will also need the following information:
1 mole of e^-=96,485 C
and
1 mole of Cr=52.00g
Calculate the number of moles that 4.94mg equates too:
4.94 mg=4.94 x 10^-3g of chromium*(1 mol/52.00g)=9.50 x 10^-5 mole of Cr
How many moles of electrons are need to produce 9.50 x 10^-5 mole of Cr? Solve for moles of electrons:
9.50 x 10^-5 mole of Cr*(6 moles of e^-/2 mole of Cr)=2.85 x 10^-4 moles of e^-
Whats the charge of 2.85 x 10^-4 moles of electrons? Use Faraday's constant:
2.85 x 10^-4 moles of e^-*(96,485 C/1 mole of e^-)=2.750 x 10^1 C
Since current (A)=charge (C)/time (s), solve for time:
A=C/s
C/A=s
2.750 x 10^1 C/0.234 A=time (s)
1.18 x 10^2 s=118s=time <= 3 significant figures</span>
Answer: hey so I’m taking the same test as you right now. I’m on that question and I searched it up and came on here. Would you mind telling me the answer?
Curd, lemon juice, orange juice and vinegar taste sour. These substances taste sour because they contain acids. The chemical nature of such substances is acidic. The word acid comes from the Latin word acere which means sour.
