Question

How many amperes would be needed to produce 60.0 grams of magnesium during the electrolysis of molten mgcl 2 in 2.00 hours?

Answer 1

Answer:

$\boxed{\text{66.2 A}}$

Explanation:

1. Write the equation for the reaction.

M_r:                 24.30

          MgCl₂ ⟶ Mg + Cl₂

m/g:                   60.0

2. Calculate the moles of Mg

Moles of Mg = 60.0 g Mg × (1 mol Mg/ 24.30 g Mg) = 2.469 mol Mg

3. Calculate the moles of electrons

Moles of electrons = 2.469 mol Mg × (2 mol electrons/1 mol Mg)

= 4.938 mol electrons

4. Calculate the number of coulombs

Q = 4.938 mol electrons × (96 485 C/1 mol electrons) = 476 500 C

5. Calculate the current required

Q  = It

I = Q/t

t = 2.00 h × (60 min/1h) × (60 s/1 min) = 7200 s

I = 476 500 C/7600 s= 66.2 C/s = 66.2 A

You need a current of $\boxed{\textbf{66.2 A}}$.