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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: finderwest on October 07, 2012, 10:35:45 PM

Title: Theoretical Mass of a Product
Post by: finderwest on October 07, 2012, 10:35:45 PM
Ok, I've been stuck on this problem for a bit. Tried looking how to do it in the text book to no avail.
I'll Start by posting the reaction and what steps I took.
Trying to find a theoretical yield for NiCl2*6H2O + 3C2H8N2 --> Ni(C2H8N2)3 +6H2O Starting with 2.272grams of the NiCl2*6H2O and 9.23mL of 3C2H8N2 at a density of 0.950g/mL...

First step was to calculate the molar mass of both reactants and product that was isolated. The Ni(C2H8N2)3. For the NiCl2*6H2O I got a mass of 237.69 g. The 3C2H8N2 was a bit different as I only had a volume and density. 9.23mL at a 0.950 density. For the mass, I multiplied the density and volume to get 8.7685g.

from here, things get fuzzy but here are the steps I took so far...
Find moles of reactant A
 2.272g NiCl2*6H2Ox 1 mole NiCl2*6H2O/237.68g NiCl2*6H20 =0.00956 moles NiCl2*6H20

Find moles of reactant B
8.769g 3C2H8N2 x 1 mole 3C2H8N2/63.098g 3C2H8N2 = 0.13897 mol 3C2H8N2

From here, I'm lost.

Please help. Thanks in advance!
Title: Re: Theoretical Mass of a Product
Post by: Hunter2 on October 08, 2012, 01:01:03 AM
This is a minimum maximum question.

Start with the nickel chloride and calculate how much moles it is and how much moles of the organic substance you would need. Compare this number with the existing moles of the organic substance. Is it larger, equal or lower?
Title: Re: Theoretical Mass of a Product
Post by: Borek on October 08, 2012, 03:54:38 AM
Quote from: Hunter2 on October 08, 2012, 01:01:03 AM
This is a minimum maximum question.

AKA limiting reagent.

Compare http://www.chembuddy.com/?left=balancing-stoichiometry&right=limiting-reagents
Title: Re: Theoretical Mass of a Product
Post by: finderwest on October 08, 2012, 07:53:45 AM
Made an error when posting.. Put in 2.272 g instead of 2.727 g....

Ok, I've been stuck on this problem for a bit. Tried looking how to do it in the text book to no avail.
I'll Start by posting the reaction and what steps I took.
Trying to find a theoretical yield for NiCl2*6H2O + 3C2H8N2 --> Ni(C2H8N2)3 +6H2O Starting with 2.727grams of the NiCl2*6H2O and 9.23mL of 3C2H8N2 at a density of 0.950g/mL...

First step was to calculate the molar mass of both reactants and product that was isolated. The Ni(C2H8N2)3. For the NiCl2*6H2O I got a mass of 237.69 g. The 3C2H8N2 was a bit different as I only had a volume and density. 9.23mL at a 0.950 density. For the mass, I multiplied the density and volume to get 8.7685g.

from here, things get fuzzy but here are the steps I took so far...
Find moles of reactant A
 2.727g NiCl2*6H2Ox 1 mole NiCl2*6H2O/237.68g NiCl2*6H20 =0.01147 moles NiCl2*6H20

Find moles of reactant B
8.769g 3C2H8N2 x 1 mole 3C2H8N2/63.098g 3C2H8N2 = 0.13897 mol 3C2H8N2

From here, I'm lost.

Please help. Thanks in advance!

*********

So, I attempted to find the limiting reactant....

Title: Re: Theoretical Mass of a Product
Post by: Borek on October 08, 2012, 08:37:34 AM
Quote from: finderwest on October 08, 2012, 07:53:45 AM
So, I attempted to find the limiting reactant....

And?
Title: Re: Theoretical Mass of a Product
Post by: DrCMS on October 08, 2012, 11:49:30 AM
Also recheck the ethylenediamine molecular weight, not that it changes the answer.  But having the wrong formula for the Nickel complex formed does so re-check that.  You start with Ni2+ in the starting material does that change for the product?
Title: Re: Theoretical Mass of a Product
Post by: finderwest on October 08, 2012, 12:22:40 PM
Ok didn't get to post the other calculations...
I made some progress.

0.13897 mo C2H8N2 x (1mol Ni(C2H8N2)3Cl2/3 mol C2H8N2) = 0.046323 mol Ni(C2H8N2)3Cl2

Then multiplied 0.046323 x 309.90 g. = 14.356g Ni(C2H8N2)3Cl as the result of the ratio of the moles.