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Synthesis of aquapentaamminecobalt(III) Nitrate Name Pre-lab out ld of crude pro

ID: 517732 • Letter: S

Question

Synthesis of aquapentaamminecobalt(III) Nitrate Name Pre-lab out ld of crude product 18g& need 20 ml of1 M NHs (aq per gram for the (aq yhe of 1M NHs (aq) will you need? How much 6 M NHs you will you need to step. How many ml solution? dilute to make this amount of 1 M 1) Y NVA amb 30 of 2) the yield of product in the above, what amount of 16 M nitric acid would nee to be added to the solution to neutralize the added NH, (aq)? 3.) In actual practice, a recrystallization step works best when you dissolve your product in a

Explanation / Answer

20mL 1M NH3 is needed to recrystallize 1 gm product.

Amount of NH3 required to recrystallize 1.8gm product = 1.8 gm * 20mL/gm = 36 mL

M1V1 = M2V2

where M1 and V1 is the concentration and molarity of diluted solution. M2 and V2 is the molarity and volume of concentrated soslution.

V2 = M1V1/M2 = 36mL * 1M / 6M = 6 mL

So, to make this solution 6 mL concentrated NH3 should be diluted to 36 mL by adding 30 mL of water.

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according to the balanced equation 2 moles of product is formed from 2 moles of HNO3.

molar mass of Co(NH3)5(H2O)(NO3)3 = 348.12g/mol

Moles of product formed = 1.8 gm/ 348.12 g/mol = 5.17*10^-3 moles

moles of HNO3 used = 5.17*10^-3 moles

Volume of nitric acid required = moles /molarity = 5.17*10^-3 moles/ 16M =3.23*10^-4 L= 0.323 mL