46 and the maximum wavelength was 520 nm 2cono3 2 6nh

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The percent yield was 1.46%, and the maximum wavelength was 520 nm. 2Co(NO3) 2 + 6NH 3 + 2(NH 4 ) 2 CO 3 + H 2 O 2 → 2[Co(NH 3 ) 4 CO 3 ]NO 3 + 2NH 4 NO 3 + 2H 2 O Data/ Observations 2.15 g ammonium carbonate 0.5 g ammonium carbonate (divided into 10 fairly equal amounts to be added during the heating) 1.03 g cobalt (II) nitrate 5 mL concentrated ammonium Final weight of coordinate compound: 1.99 g Electronic spectrum of complex: Wavelength % Transmittance Absorbance 430 nm 56 0.25 445 nm 52.5 0.28 460 nm 51.5 0.29 475 nm 50 0.30 490 nm 45 0.35 505 nm 42 0.376 520 nm 41.5 0.382 535 nm 44 0.36 550 nm 49.5 0.31 565 nm 57.5 0.24 580 nm 63 0.201 O O H 3 N H 3 N NH 3 NH 3 Co C O NO 3
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595 nm 69.5 0.16 610 nm 73 0.14 625 nm 75 0.12 640 nm 77 0.11 655 nm 78 0.108 Tables Sample Calculations Theoretical Yield: 1.002 g Co(NO 3 ) 2 x (1 mole/183 g Co(NO 3 ) 2 ) x ( 1 mole cobalt complex/1 mole Co(NO 3 ) 2 ) x (248 g/1 mole cobalt complex) = 1.36 g Actual Yield: 1.99 g Percent Yield: Actual Yield/ Theoretical Yield x 100= 1.99g/1.36g = 1.46% λ max: 520 nm Energy gap: hc/ λ = (6.626 x 10 -34 Js)(2.998 x 10 8 )/(520 x 10 -9 m) = 3.784 x 10 -19 J/photon x (6.022 x 10 23 photons/mole) x (1 KJ/1000 J) = 228 KJ/mole Discussion The coordination number of cobalt is six; therefore, ligands attach to cobalt at six different positions and cobalt forms octahedral complexes. Carbonate is a bidentate ligand so it binds to cobalt at two sites.
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