Please solve and show how you got to your final answer. 6. Describe how you woul

Question

Please solve and show how you got to your final answer.

6. Describe how you would prepare the following solutions:

a. 500mL of 25 ppm Cu from copper metal

b. 100mL of 20ppm Fe from 1000ppm certified Fe stock solution

c. 250mL of a 50ppm solution of Ni from pure solid NiCl2 6H2O (FW=237.71g/mol)

d. 500mL of a 0.01000M EDTA from the pure solid (FW=372.23 g/mol)

11. To determine the concentration of ethanol in cognac, a 5.00mL sample of cognac is diluted to 0.500L. Analysis of the diluted cognac gives an ethanol concentration of 0.0844 M. What is the molar concentration of ethanol in the undiluted cognac.

Please solve and show how you got to your final answer. Describe how you would prepare the following solutions: 500mL of 25 ppm Cu from copper metal 100mL of 20ppm Fe from 1000ppm certified Fe stock solution 250mL of a 50ppm solution of Ni from pure solid NiCl2 6H2O (FW=237.71g/mol) 500mL of a 0.01000M EDTA from the pure solid (FW=372.23 g/mol) To determine the concentration of ethanol in cognac, a 5.00mL sample of cognac is diluted to 0.500L. Analysis of the diluted cognac gives an ethanol concentration of 0.0844 M. What is the molar concentration of ethanol in the undiluted cognac.

Explanation / Answer

6)

a.

25 ppm = 0.024971475 g/L

so,

add 0.024971475/2= 0.0125 g of Cu metal to 500 ml water

b.

20 ppm = 0.01997718 g/L

so,

100 ml contains  0.01997718*0.1=  0.001997718 grams

1000 ppm = 0.998859 g/L

volume of stock needed = 0.001997718/0.998859 = 0.002 L = 2 ml

so,

preparation : 2ml of stock + 98 ml of water

11)

diluted cognac Concentration = Cd = 0.0844 M = 0.0844 moles per Litre

so,

moles in 0.5 L = 0.0844/2 = 0.0422 moles

so,

Concetration of undiluted Cognac = 0.0422/(5*10^-3) = 8.44 M

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