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Chem 1C – Chapter 19 – CLAS
e-mail: [email protected]
website: clas.sa.ucsb.edu/staff/terri/
1. Which of the following substances can NOT act as a ligand?
a. H2O
b. OH–
c. CO
d. NH4+
e. Br–
2. Which of the following can act as a chelate? Circle all that apply.
a. NH2CH2CH2NH2 bidentate
b. C2O42– bedentate
c. NH2CH2CH2NHCH2CH2NH2 tridentate
d. SCN–
3. Write the chemical formula for the following:
a. lithium hexahydroxoferrate(III) Li3[Fe(OH)6]
b. diamminedichloro(ethylendiamine)chromium(III) sulfate [Cr(NH3)2Cl2(en)] 2SO4
c. potassium tetrabromodicyanoplatinate(II) K2[PtBr2(CN)2]
d. bis(ethylenediamine)oxalatomanganese(IV) nitrate [Mn(en)2(ox)](NO3)2
4. For each of the following 1) what is the oxidation state on the transition metal 2) determine the coordination number
and 3) provide a name:
+
triamminebromoplatinum(II) ion
a. [Pt(NH ) Br]
3 3
b. K[Co(en)BrCl ] potassium bromotrichloro(ethylenediamine)cobaltate(III)
3
c. [Ni(CO)4] Br2 tetracarbonylnickel(II) bromide
d. Na[Mn(C2O4)2(CN)2] sodium dicyanobisoxaltomangenate(V)
e. [Cu(NH3)4(H2O)2][PtI6] diamminediaquacopper(II) hexaiodoplatinate(IV)
5. Which of the following can NOT form linkage isomers?
a. SCN–
b. NO2–
c. NO3–
d. all can form linkage isomers
6. Rank the following 0.1M aqueous solutions by their conductivity in water.
I. [Cr(H2O)6]Cl3
II. [Cr(H2O)4Cl2]Cl•(H2O)2
III. [Cr(H2O)5Cl]Cl2•H2O
I > III > II
What type of isomers are illustrated above? Coordination isomers
7. Which of the following substances can have geometric isomers?
a. [Co(NH3)5Cl]SO4
b. [Co(NH3)6]Cl3
c. Li[Co(NH3)3Cl3]
d. K[Co(NH3)2Cl4]
e. Na3[CoCl6]
8. Give the number of geometric isomers for the octahedral compound [MA2B2C2], where A, B, and C represent ligands.
a. 1
b. 2
c. 3
d. 5
e. 6
9. For the process Co(NH3)5Cl2+ + Cl–  Co(NH3)4Cl2+ + NH3, what would be the ratio of cis to trans isomers in the
product?
a. 1:1
b. 1:2
c. 1:4
d. 4:1
e. 2:1
10. Which of the following statements about the complex ion Co(en)2Cl2+ is true?
(en = ethylenediamine, NH2CH2CH2NH2)
a. The complex ion contains Co(I).
b. The complex ion exhibits cis and trans geometric isomers, but no optical isomers.
c. The complex ion exhibits two geometric isomers (cis and trans) and two optical isomers.
d. The geometric isomers of the complex ion have identical chemical properties.
11. The compound Co(NH3)4Cl3 (233.44g/mol) has several structural isomers. A solution is made by dissolving 0.875 g
of one of the isomer in 25.0 g of water. The solution freezes at -0.56 °C. (Kf = 1.86 °C kg/mol) Which of the
following is the correct structural isomer?
a. [Co(NH3)4Cl3]
b. [Co(NH3)4Cl2]Cl
c. [Co(NH3)4Cl]Cl2
d. [Co(NH3)4]Cl3
ΔTf = - kfim
-0.56C = -(1.86 Ckg/mol)(i)(0.875g/233.44g/mol)/(0.025kg)
i = 2 => [Co(NH3)4Cl2]Cl
12. Draw the d orbital diagrams according to the crystal field model in order to predict how many unpaired electrons are
in each of the following:
a. [Fe(CN)6]3-
b. [CoBr6]4-
c. [Mn(en)2]3+ (tetrahedral)
13. An orange complex and a violet complex were both found to have ferric ion as their central metal; which one absorbs
light with a longer wavelength?
The color you see is the complimentary color of what is absorbed - If you see orange it is absorbing blue
and if you see violet it is absorbing yellow – yellow is a longer wavelength than blue – so the violet complex
absorbs the longer wavelength
14. Solutions of [Co(NH3)6]3+ , [Co(NO2)6]3-and [CoF6]3- are colored. The solutions were red, yellow and blue. Match the
solution to the color.
Red absorbs green
Yellow absorbs violet
Blue absorbs orange
Of the colors absorbed violet is the highest energy – therefore it must have the strongest ligand - [Co(NO2)6]3Of the colors absorbed orange is the lowest energy – therefore it must have the weakest ligand – [CoF6]3Red complex - [Co(NH3)6]3+
Yellow complex – [Co(NO2)6] 3Blue complex – [CoF6]315. The complex ion [Zn(H2O)6]2+ is colorless whereas [Ni(H2O)6]2+ is green, explain. In order to be colored the
transition metal must have ligands and have 1-9 electrons in d orbital(s). Since zinc has 10 d electrons it will be colorless
16. A crystal that contains a complex ion is known to absorb 266 kJ/mol. Determine the color of the crystal.
ℎ𝑐
(6.626 𝑥 10−34 𝐽𝑠)(3 𝑥108 𝑚/𝑠)
λ=
⇒
λ=
= 4.5 𝑥 10−7𝑚 𝑜𝑟 450 𝑛𝑚 ⇒ absorbs blue light so
266,000𝐽
𝑚𝑜𝑙
𝛥𝐸
𝑥
23
𝑚𝑜𝑙
the complex appears orange
6.022 𝑥 10