Question

In: Chemistry

A mixture is prepared by combining 3.0 mL of 0.0050 M NaSCN solution with 4.0 mL...

A mixture is prepared by combining 3.0 mL of 0.0050 M NaSCN solution with 4.0 mL of 0.0030 M Fe(NO3)3 solution, and 3.0 mL of 0.10 M HNO3

a). if Keq = 405, determine the equilibrium concentration of FeSCN2+ in the solution. (keep 4 decimal places)

b). if Keq=282, determine the equilibrium concentration of Fe3+ in the solution. (keep 4 decimal places)

c). if Keq = 343, determine the equilibrium concentration of SCN-- in the solution. (keep 4 decimal places)

Expert Solution

Total volume 10 mL

Initial values, before reaction:

[Fe3+] = 0.0030 M x 4mL/10mL = 0.0012 M

[SCN-] = 0.0050 M x 3mL/10 mL= 0.0015 M

Fe3+ + SCN- = FeSCN2+
0.0012M 0.0015 M 0 initial

0 0.0003 M 0.0012M after reaction

X 0.0003+X 0.0012 – X at equilibrium

K = (0.0012 – X) / ( X(0.0003+X)= 405

405X²+ 1.1215X-0.0012= 0

Solving the quadratic equation for X

X= 0.0008. (NeglacNeg the negative X value)

Now,

[FeSCN2+] = (0.0012- X) M.

= 0.0012- 0.0008 M

= 0.0004 M

Similarly, if K= 282

We have, 282= (0.0012- X)/(X(0.0003+X).

(0.0012- X)= 0.0846 X+ 282 X²

Solving the equation to get X= 0.0008.

Therefore, [Fe3+]= X= 0.0008 M.

Also, if K= 343,

We have, 343= (0.0012- X)/(X(0.0003+ X))

X= 0.00085.

Therefore, [SCN-]= 0.0003+X= 0.0003+ 0.00085

= 0.00115 M.

queen_honey_blossom answered 2 years ago

In a buffer solution prepared from 10 mL of 3.0 M benzoic acid (HC6H5CO2) added to...

In a buffer solution prepared from 10 mL of 3.0 M benzoic acid (HC6H5CO2) added to 20 mL of a 2.0 M sodium benzoate (NaC6H5CO2) and diluted to a total volume of 200mL- Calculate each of the following: a. The original pH of the buffer solution b. The pH upon addition of 8.0 mL of 2.0 M NaOH to part a c. The pH upon addition of 30.0 mL of 2.0 M HCl to part a

In a buffer solution prepared from 10 mL of 3.0 M Pyridine (C5H5N) added to 20...

In a buffer solution prepared from 10 mL of 3.0 M Pyridine (C5H5N) added to 20 mL of 2.0 M Pyridine Hydrochloride (C5H5NHCl) and diluted to a total volume of 200 mL- Calculate each of the following: a. The original pH of the buffer solution b. The pH upon addition of 25.0 mL of 2.0 M NaOH to part a c. The pH upon addition of 10.0 mL of 2.0 M HCl to part b

You prepare an equilibrium mixture by combining 4.00 mL 0.00129 M Fe3+ with 0.100 mL 0.00582...

You prepare an equilibrium mixture by combining 4.00 mL 0.00129 M Fe3+ with 0.100 mL 0.00582 M SCN-. What is [Fe3+]o for this mixture? Enter the numerical value to 3 significant figures, without units. (You may enter the value using E-format scientific notation, e.g., 1.23×10-4 would be entered as 1.23E-4 -- no spaces, capital E.)

A. A solution is made by combining 15.0 mL of 18.5 M acetic acid with 5.50...

A. A solution is made by combining 15.0 mL of 18.5 M acetic acid with 5.50 g of sodium acetate and diluting to a total volume of 1.50 L. Calculate the pH of the solution. B.A 115.0 −mL sample of a solution that is 3.0×10−3 M in AgNO3 is mixed with a 225.0 −mL sample of a solution that is 0.14 M in NaCN. After the solution reaches equilibrium, what concentration of Ag+(aq) remains?

A. Calculate the pH of a solution formed by combining 0.125 mL of 0.55 M HI...

A. Calculate the pH of a solution formed by combining 0.125 mL of 0.55 M HI with 0.400 mL of 0.14 M KOH at 25°C. B. Calculate the pH of a solution formed by combining 0.125 mL of 0.55 M HI with 0.400 mL of 0.18 M KOH at 25°C. C. A 50.00-mL sample of 0.0750 M HCN was titrated with 0.3995 M NaOH. What is the pH of the resulting solution after 5.00 mL of NaOH were added at...

A mixture is made by combining 11.5 mL of 8.5×10−3 M KSCN, 6.3 mL of 3.7×10−2...

A mixture is made by combining 11.5 mL of 8.5×10−3 M KSCN, 6.3 mL of 3.7×10−2 M Fe(NO3)3, and 10.4 mL of 0.397 M HNO3. Calculate the concentraion of Fe3+ in the solution.

A mixture is made by combining 19.9 mL of 1.2×10−3 M KSCN, 8.5 mL of 8.1×10−2...

A mixture is made by combining 19.9 mL of 1.2×10−3 M KSCN, 8.5 mL of 8.1×10−2 M Fe(NO3)3, and 11 mL of 0.198 M HNO3. Calculate the concentration of Fe3+ in the solution.

A mixture is made by combining 14 mL of 1.9×10−3 M KSCN, 7.8 mL of 9.1×10−2...

A mixture is made by combining 14 mL of 1.9×10−3 M KSCN, 7.8 mL of 9.1×10−2 M Fe(NO3)3, and 11.7 mL of 0.475 M HNO3. Calculate the concentraion of Fe3+ in the solution.

A 125.0 −mL sample of a solution that is 3.0×10^−3 M in AgNO3 is mixed with...

A 125.0 −mL sample of a solution that is 3.0×10^−3 M in AgNO3 is mixed with a 230.0 −mL sample of a solution that is 0.12 M in NaCN. After the solution reaches equilibrium, what concentration of Ag+(aq) remains?

A 125.0 −mL sample of a solution that is 3.0×10−3 M in AgNO3 is mixed with...

A 125.0 −mL sample of a solution that is 3.0×10−3 M in AgNO3 is mixed with a 230.0 −mL sample of a solution that is 0.12 M in NaCN. After the solution reaches equilibrium, what concentration of Ag+(aq) remains? Express your answer using two significant figures.