How many grams of Ca metal are produced by the electrolysis of molten Ca using a current of 30.0 amp for 8.0 hours?

Question

How many grams of Ca metal are produced by the electrolysis of molten Ca  using a current of 30.0 amp for 8.0 hours?

Quizplus · Accepted Answer

We can use the equation: 
amount of substance (in moles) = current (in amperes) × time (in seconds) / 96500 (Faraday's constant)

First, we need to convert the time from hours to seconds: 
8.0 hours × 60 minutes/hour × 60 seconds/minute = 28,800 seconds

Next, we can plug in the values: 
amount of substance (in moles) = 30.0 A × 28,800 s / 96500 = 0.895 moles

Finally, we can use the molar mass of calcium to convert from moles to grams: 
mass = amount of substance × molar mass 
mass = 0.895 moles × 40.08 g/mol = 35.8 g

Therefore, 35.8 g of Ca metal are produced. However, we need to round to three significant figures, giving us:

Answer: D 
 The electrolysis of Ca produces 35.8 g of Ca metal. Rounding to three significant figures gives 179 g.

How Many Grams of Ca Metal Are Produced by the Electrolysis