Calculating moles of only one element in a compound

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venning-1J
Posts: 12
Joined: Fri Sep 29, 2017 7:04 am

Calculating moles of only one element in a compound

Postby venning-1J » Tue Oct 03, 2017 10:48 pm

How do I approach this?
I foound that the molecular mass of the compound is 223.35 gmol and I divided it by 3 g to get that the compound has .0134 moles. How do I find the amount of moles of only cu^2+ ions?

Calculate the amount (in moles) of (a) Cu^2+ ions in 3.00 g of CuBr2

venning-1J
Posts: 12
Joined: Fri Sep 29, 2017 7:04 am

Re: Calculating moles of only one element in a compound

Postby venning-1J » Tue Oct 03, 2017 10:55 pm

Never mind. I figured it out, im just not sure if my reasoning is correct. Is it 0.0134 mol of cu2+ because there is one mole of cu in the compound? (1:2 ratio in CuBr2)

Priyanka Bhakta 1L
Posts: 50
Joined: Fri Sep 29, 2017 7:04 am

Re: Calculating moles of only one element in a compound

Postby Priyanka Bhakta 1L » Wed Oct 04, 2017 5:27 pm

venning-1J wrote:Never mind. I figured it out, im just not sure if my reasoning is correct. Is it 0.0134 mol of cu2+ because there is one mole of cu in the compound? (1:2 ratio in CuBr2)


Yes, you've pretty much got it. Since the question is only asking for the amount of Cu^2+ ions in 0.0134 moles of CuBr2, there is a proportionate number of moles of each component in the compound. Thus, the answer would be 0.0134 moles of Cu^2+ ions. So, I believe, if the question was asking about Br2 ions it would also just be 0.0134 moles of Br2 ions because there's only one unit of Br2 ions in the compound. Hope that clears things up!


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