Chromium can be electroplated from an aqueous solution containing sulfuric acid and chromic acid, H2CrO4. What current is required to deposit chromium at a rate of 1.25 g/min?

1mol H2CrO4 has 51.996 grams

current= coulomb/sec

How do I convert to get coulombs from the problem?

You know 96,485 Coulombs is required to plate out 51.996/6 g Cr (Cr goes from +6 in H2CrO4 to zero in Cr) = 8.666 g Cr.

You want to plate 1.25 g/min which is 1.25/60 = 0.02083 g/sec.

96,485 C x 0.02083/8.666 = ??Coulombs.
1 ampere current = 1C/sec
so you will need ?? C/sec or that much current.
Check my thinking. Check my numbers.

That makes sense, just so I understand, how did you get 8.666 g Cr? What does the +6 to 0 mean?

Well, let's think about it in a fun way! To convert grams to coulombs, we need to use a little bit of chemistry magic.

Picture this: you have a group of comedians (let's call them The Chrom-ic Comedians) lined up, ready to perform. Each comedian represents a mole of H2CrO4, which weighs approximately 51.996 grams according to your information.

Now, in order to measure the current required to deposit chromium, we need to know how many moles of H2CrO4 we're dealing with. So, we divide the given mass (1.25 g) by the molar mass of H2CrO4. This gives us the number of moles.

Once we have the number of moles, we can then say that each mole represents an electric charge of around 1 Faraday (which is approximately 96,485 coulombs) because each elemental formula unit carries one unit of electric charge.

So, if we multiply the number of moles by the charge of one mole (around 96,485 coulombs), we'll find the total charge in coulombs. And that, my friend, is the current required for depositing chromium!

To convert the mass of chromium (1.25 g) to coulombs, we need to use the concept of Faraday's Law of Electrolysis. Faraday's Law states that the amount of substance that is electroplated or dissolved during an electrolysis process is directly proportional to the total electric charge passed through the electrolyte.

The equation that represents Faraday's Law is:

Q = nF

Where:
Q is the total electric charge passed in coulombs (C)
n is the number of moles of the substance being electroplated or dissolved
F is the Faraday constant, which is approximately 96,500 coulombs per mole of electrons

Since we are given the mass of chromium (1.25 g) and the molar mass of H2CrO4 (51.996 g/mol), we can find the number of moles using the equation:

n = mass / molar mass

n = 1.25 g / 51.996 g/mol

n ≈ 0.024 moles

Now, we can calculate the total electric charge passed through the electrolyte using Faraday's Law:

Q = nF

Q = 0.024 moles × 96,500 C/mol

Q ≈ 2,316 C

Therefore, the total electric charge passed through the electrolyte (current) required to deposit chromium at a rate of 1.25 g/min is approximately 2,316 coulombs (C).

Re-read my first response. Cr goes from +6 in H2CrO4 to zero in Cr metal. That's a change of 6 electrons. The equivalent weight of a material is molar mass/delta electrons = 51.996 (I took your number and didn't check it out) or 51.996/6 = 8.666 g as the equivalent weight of Cr in this reaction.