Fe 3 aq colorless SCN aq colorless FeSCN2

Fe 3+ (aq) colorless + SCN- (aq) colorless Fe(SCN)2+ (aq)

Fe 3+ (aq) colorless + SCN- (aq) colorless Fe(SCN)2+ (aq) reddish orange

Standard Solutions for calibration curve Pg. 28 A (blank) B C D E volume of 0. 200 M Fe 3+ 10. 0 m. L volume of 0. 00200 M SCN- 0. 00 m. L 0. 50 m. L 1. 00 m. L 1. 50 m. L 2. 00 m. L 0. 200 M HNO 3 equilibrium [Fe(SCN)2+], M dilute to 25. 00 m. L mark 0. 00 4. 00 x 10 -5 8. 00 x 10 -5 12. 0 x 10 -5 16. 0 x 10 -5

Standard solutions Pg. 32 Standards [Fe(SCN)2+], M standard A 0. 00 standard B 4. 00 x 10 -5 standard C 8. 00 x 10 -5 standard D 12. 0 x 10 -5 standard E 16. 0 x 10 -5 absorbance

Standard solutions Pg. 32 Standards [Fe(SCN)2+], M absorbance standard A 0. 000 standard B 4. 00 x 10 -5 0. 196 standard C 8. 00 x 10 -5 0. 371 standard D 12. 0 x 10 -5 0. 557 standard E 16. 0 x 10 -5 0. 759

Pg. 30 Experimental Solutions Blank 1 2 3 4 5 m. L 0. 00200 M SCN- 0. 00 0. 50 1. 00 1. 50 2. 00 2. 50 m. L 0. 00200 M Fe 3+ 2. 50 m. L 0. 200 M HNO 3 2. 50 2. 00 1. 50 1. 00 0. 50 0. 00

Experimental test solutions Pg. 32 Experimental solution 1 solution 2 solution 3 solution 4 solution 5 absorbance [Fe(SCN)2+], M

Experimental test solutions Pg. 32 Experimental absorbance solution 1 0. 139 solution 2 0. 278 solution 3 0. 414 solution 4 0. 546 solution 5 0. 658 [Fe(SCN)2+], M

Experimental test solutions Pg. 32 Experimental absorbance [Fe(SCN)2+], M solution 1 0. 139 2. 96 x 10 -5 solution 2 0. 278 from graph solution 3 0. 414 from graph solution 4 0. 546 from graph solution 5 0. 658 from graph

Pg. 34 units are M Experimental test solutions 1 [Fe(SCN)2+]equil 2. 96 x 10 -5 (graph) [Fe 3+]initial [SCN-]initial [Fe 3+]equil [SCN-]equil K Average K 2 3 4 5

Experimental test solutions Pg. 32 Experimental absorbance [Fe(SCN)2+], M solution 1 0. 139 2. 96 x 10 -5 solution 2 0. 278 from graph solution 3 0. 414 from graph solution 4 0. 546 from graph solution 5 0. 658 from graph

Experimental test solutions Pg. 32 Experimental absorbance [Fe(SCN)2+], M solution 1 0. 139 2. 96 x 10 -5 solution 2 0. 278 5. 92 x 10 -5 solution 3 0. 414 from graph solution 4 0. 546 from graph solution 5 0. 658 from graph

Pg. 34 units are M Experimental test solutions 1 2 [Fe(SCN)2+]equil 2. 96 x 10 -5 5. 92 x 10 -5 (graph) [Fe 3+]initial [SCN-]initial [Fe 3+]equil [SCN-]equil K Average K 3 4 5

Pg. 30 Experimental Solutions Blank 1 2 3 4 5 m. L 0. 00200 M SCN- 0. 00 0. 50 1. 00 1. 50 2. 00 2. 50 m. L 0. 00200 M Fe 3+ 2. 50 m. L 0. 200 M HNO 3 2. 50 2. 00 1. 50 1. 00 0. 50 0. 00

Initial Concentrations for Trial 1

Pg. 34 units are M Experimental test solutions 1 2 [Fe(SCN)2+]equil 2. 96 x 10 -5 5. 92 x 10 -5 (graph) [Fe 3+]initial [SCN-]initial [Fe 3+]equil [SCN-]equil K Average K 1. 00 x 10 -3 3 4 5

Pg. 34 units are M Experimental test solutions 1 2 3 4 5 1. 00 x 10 -3 [Fe(SCN)2+]equil 2. 96 x 10 -5 5. 92 x 10 -5 (graph) [Fe 3+]initial [SCN-]initial [Fe 3+]equil [SCN-]equil K Average K 1. 00 x 10 -3

Pg. 30 Experimental Solutions Blank 1 2 3 4 5 m. L 0. 00200 M SCN- 0. 00 0. 50 1. 00 1. 50 2. 00 2. 50 m. L 0. 00200 M Fe 3+ 2. 50 m. L 0. 200 M HNO 3 2. 50 2. 00 1. 50 1. 00 0. 50 0. 00

Initial Concentrations for Trial 1

Pg. 34 units are M Experimental test solutions 1 2 3 4 5 1. 00 x 10 -3 [Fe(SCN)2+]equil 2. 96 x 10 -5 5. 92 x 10 -5 (graph) [Fe 3+]initial [SCN-]initial [Fe 3+]equil [SCN-]equil K Average K 1. 00 x 10 -3 2. 00 x 10 -4

[ ], M Fe 3+ (aq) + SCN- (aq) Fe(SCN)2+ (aq) initial 1. 00 x 10 -3 2. 00 x 10 -4 0 change x x +x equilibrium 1. 00 x 10 -3 x 2. 00 x 10 -4 x x x = [Fe(SCN)2+]equil (obtained from graph)

Equilibrium Concentrations for Trial 1 [Fe 3+]equil = [Fe 3+] initial – [Fe(SCN)2+]equil [Fe 3+]equil = 1. 00 x 10 -3 M – 2. 96 x 10 -5 M = 9. 70 x 10 -4 M

Pg. 34 units are M Experimental test solutions 1 2 3 4 5 1. 00 x 10 -3 [Fe(SCN)2+]equil 2. 96 x 10 -5 5. 92 x 10 -5 (graph) [Fe 3+]initial 1. 00 x 10 -3 [SCN-]initial 2. 00 x 10 -4 [Fe 3+]equil 9. 70 x 10 -4 [SCN-]equil K Average K

Equilibrium Concentrations for Trial 1 [SCN ]equil = [SCN ] initial – [Fe(SCN)2+]equil [SCN ]equil = 2. 00 x 10 -4 M – 2. 96 x 10 -5 M = 1. 70 x 10 -4 M

Pg. 34 units are M Experimental test solutions 1 2 3 4 5 1. 00 x 10 -3 [Fe(SCN)2+]equil 2. 96 x 10 -5 5. 92 x 10 -5 (graph) [Fe 3+]initial 1. 00 x 10 -3 [SCN-]initial 2. 00 x 10 -4 [Fe 3+]equil 9. 70 x 10 -4 [SCN-]equil 1. 70 x 10 -4 K Average K

Determine the numerical value of the equilibrium constant, K = 179

Pg. 34 units are M Experimental test solutions 1 2 3 4 5 1. 00 x 10 -3 [Fe(SCN)2+]equil 2. 96 x 10 -5 5. 92 x 10 -5 (graph) [Fe 3+]initial 1. 00 x 10 -3 [SCN-]initial 2. 00 x 10 -4 [Fe 3+]equil 9. 70 x 10 -4 [SCN-]equil 1. 70 x 10 -4 K 179 Average K