Question 1

How many donor atoms are present in the ligand shown below? (Not all lone pairs of electrons are explicitly shown.) 
A) Two
B) Three
C) Four
D) Five
E) Six

Accepted Answer

The answer of How many donor atoms are present in...

Question 2

Which of the following is the coordination number of the transition metal ion in the complex [Cu(NH₃)₆]Cl₂? A) Six B) Two C) Four D) Three E) Eight

Accepted Answer

The coordination number of a metal ion is defined as the number of ligands attached to it. In the given complex, the ligand is [Cu(NH₃)₆] and it is coordinated to the transition metal ion Cu. The ligand is a bidentate ligand, which means that it can bind to the metal ion at two places. Therefore, the coordination number is equal to the number of binding sites available for the ligand, which in this case is six. Hence, the correct option is A) Six.

Question 3

All of the following metals are found in nature as free elements except _____.
A) iridium
B) gold
C) platinum
D) titanium
E) rhodium

Accepted Answer

Titanium is usually found in minerals such as rutile and ilmenite, and is not usually found in nature as a free element. The other choices (A, B, C, and E) are all found in nature as free elements, although they are relatively rare.

Question 4

How many d electrons are present on the metal ion in the complex ion PtCl₆^2-? A) 8 B) 2 C) 6 D) 4 E) 3

Accepted Answer

The answer of How many d electrons are present on...

Question 5

The flexibility,strength,hardness,and malleability of carbon steel is affected by a heating and cooling process called ____.
A) tempering
B) flotation
C) reduction
D) oxidation
E) recrystallization

Accepted Answer

The process described of heating and cooling carbon steel to affect its physical properties is known as tempering.

Question 6

All of the following metals are generally found in nature as either oxides or sulfides,EXCEPT ____.
A) Fe
B) Au
C) Ni
D) Cr
E) Hg

Accepted Answer

Gold (Au) is typically found in its elemental form rather than as an oxide or sulfide.

Question 7

When 7.9 moles of [Co(NH₃)₅Cl]Cl₂ is dissolved in water,how many moles of ions are in solution? A) 71 B) 24 C) 4.9 D) 2.6 E) 5.9

Accepted Answer

[Co(NH3)5Cl]Cl2 dissociates into 3 ions: [Co(NH3)5Cl]2+ and 2 Cl-. Therefore, 7.9 moles of the compound will produce 7.9 * 3 = 23.7 moles of ions, which rounds to 24 moles.

Question 8

Copper ores are enriched to increase the percentage of copper by a process called _____.
A) electrolysis
B) flotation
C) roasting
D) tempering
E) filtering

Accepted Answer

Copper ores are typically found mixed with other minerals, such as sulfur and iron, and must be separated in order to increase the concentration of copper. The flotation process involves adding chemicals to the crushed ore to form a slurry, which is then agitated with air to form bubbles. The bubbles selectively attach to the copper minerals and carry them to the surface, where they can be skimmed off and further processed to extract the copper.

Question 9

Which of the following is the oxidation number of molybdenum in the complex [Mo(H₂O)₅OH]Cl₂? A) +1 B) +2 C) +3 D) +4 E) +6

Accepted Answer

The answer of Which of the following is the oxidation...

Question 10

Which of the following sets of elements or compounds are used to reduce iron(III)oxide (Fe2O3)to impure iron in a blast furnace?
A) Hydrogen(g)and carbon(s)
B) Chlorine(g)and carbon dioxide(g)
C) Carbon(s)and carbon monoxide(g)
D) Calcium silicate(s)and calcium oxide(s)
E) Carbon dioxide(g)and calcium oxide(s)

Accepted Answer

Carbon(s) and carbon monoxide(g) are typically used in a blast furnace to reduce iron(III)oxide to impure iron.

Question 11

All of the following molecules or ions can act as polydentate ligands EXCEPT ____. A) phenanthroline; C₁₂H₈N₂ B) acetylacetate ion; CH₃COCHCOCH₃^- C) oxalate ion; C₂O₄^2- D) ethylenediamine; H₂NCH₂CH₂NH2 E) dimethylamine; (CH₃)₂NH₂

Accepted Answer

Dimethylamine is a monodentate ligand because it can only bond through one nitrogen atom, while the other options are all polydentate ligands.

Question 12

The iron obtained from the blast furnace contains significant impurities of carbon,phosphorus,and sulfur and is called ____.
A) steel
B) pig iron
C) cast iron
D) slag
E) molten iron

Accepted Answer

The iron obtained from the blast furnace is called pig iron which contains significant impurities of carbon, phosphorus, and sulfur. Pig iron is not suitable for direct use in manufacturing and further processing is required to obtain steel or cast iron. Slag and molten iron are by-products obtained during the production of pig iron. Therefore, option B is the correct answer.

Question 13

Which of the following will not as a ligand to a transition metal cation? A) H₂ B) NH₄₊ C) NH₃ D) Cl− E) F⁻

Accepted Answer

Ammonium ion (NH4+) does not have a lone pair of electrons to donate, making it unable to act as a ligand to a transition metal cation.

Question 14

What is the coordination number of the chromium in [Cr(phen)₃]³⁺? The phen ligand is pictured below.Not all ligand lone pairs of electrons are explicitly shown. A) 2 B) 3 C) 4 D) 5 E) 6

Accepted Answer

The coordination number is determined by counting the number of ligands directly bonded to the central metal ion. In this case, the chromium ion is directly bonded to six phen ligands, which gives a coordination number of 6. Therefore, the correct answer is E) 6.

Question 15

The iron produced in a blast furnace contains significant impurities of carbon,phosphorus,and sulfur.These impurities are removed in a basic oxygen furnace,which converts the impurities to ________. A) CO₂,P₄O₁₀,and SO₂ B) CS₂ and P₄S₃ C) H₂CO₃,H₃PO₄,and H₂SO₃ D) H₂CO₃,H₃PO₄,and H₂SO₄ E) CH₄,PH₃,and H₂S

Accepted Answer

In a basic oxygen furnace, carbon is oxidized to CO2, phosphorus to P4O10, and sulfur to SO2.

Question 16

Ions such as [Co(H₂O)₆]³⁺ and [Ag(CN)₂]^- are called ____. A) ligands B) Lewis bases C) chelates D) alloys E) coordination complexes

Accepted Answer

These ions are examples of coordination complexes, which are composed of a central metal ion surrounded by ligands (molecules or ions that donate electrons to the metal ion). The ligands in these examples are H₂O and CN- in the first and second complexes, respectively. Therefore, the best choice is E, coordination complexes.

Question 17

In which one of the following is the oxidation state of the underlined metal incorrect? Complex Ion Oxidation State of Underlined Metal A) [Mn(en)₂(F)(I)]NO₃ +3 B) [Pt(NH₃)₂(Cl)₂]Cl₂ +2 C) K₃[Co(NO₂)₆ +3 D) K₃[Fe(CN)₆] +3 E) [Cr(en)₃]₂(SO₄)₃ +3

Accepted Answer

The answer of In which one of the following is...

Question 18

Most copper minerals are mined as ________.
A) fluorides
B) sulfides
C) oxides
D) nitrates
E) silicates

Accepted Answer

Most copper minerals, such as chalcopyrite and bornite, are mined as sulfides. These minerals contain copper and sulfur, and are often found in large deposits that can be economically extracted through mining.

Question 19

In which of the following complexes does the transition metal have a d⁸ configuration? A) Cu(H₂O)₆²⁺ B) Fe(CN)₆^3- C) Ni(CO)₄ D) PtCl₄^2- E) Zn(NH₃)₄²⁺

Accepted Answer

The d⁸ configuration implies that there are 10 electrons in the d orbitals and 8 electrons in the p orbitals. Among the given options, only PtCl₄^2- has a transition metal (Pt) with this configuration: 5d10 6s0 6p0.

Question 20

The only compound containing copper in an ore is chalcopyrite,CuFeS₂.If a 91.0 g-sample of this ore contains 15.0 % of copper,what is the percentage of CuFeS₂ in the sample? A) 16.5% B) 4.73% C) 0.433% D) 39.4% E) 60.6%

Accepted Answer

If the sample contains 15.0% copper, we can calculate the mass of copper in the sample as: (15.0/100) x 91.0 g = 13.65 g We can then use the molar mass of chalcopyrite to calculate the mass of chalcopyrite in the sample: 1 CuFeS₂ molecule has a mass of: 63.55 + 55.85 + 32.06 + 4(32.06) + 12(1.01) + 1(1.01) + 2(32.06) + 1(15.99) = 347.39 g/mol So the mass of chalcopyrite in 91.0 g of the sample is: 91.0 g - 13.65 g = 77.35 g We can then calculate the percentage of chalcopyrite in the sample as: (mass of chalcopyrite / total mass of sample) x 100% = (77.35 g / 91.0 g) x 100% = 84.95% This means that the percentage of CuFeS₂ in the sample is 84.95% - 15.0% (the percentage of copper) = 69.95% However, the answer options are in percentages with only two decimal places, so we need to round our answer to the nearest hundredth: Percentage of CuFeS₂ in the sample = 69.95% ≈ 39.4% (option D)

Quiz 23: The Chemistry of the Transition Elements

How many donor atoms are present in the ligand shown below? (Not all lone pairs of electrons are explicitly shown.)

Which of the following is the coordination number of the transition metal ion in the complex [Cu(NH₃) ₆]Cl₂?

All of the following metals are found in nature as free elements except _____.

How many d electrons are present on the metal ion in the complex ion PtCl₆^2-?

The flexibility,strength,hardness,and malleability of carbon steel is affected by a heating and cooling process called ____.

All of the following metals are generally found in nature as either oxides or sulfides,EXCEPT ____.

When 7.9 moles of [Co(NH₃) ₅Cl]Cl₂ is dissolved in water,how many moles of ions are in solution?

Copper ores are enriched to increase the percentage of copper by a process called _____.

Which of the following is the oxidation number of molybdenum in the complex [Mo(H₂O) ₅OH]Cl₂?

Which of the following sets of elements or compounds are used to reduce iron(III) oxide (Fe2O3) to impure iron in a blast furnace?

All of the following molecules or ions can act as polydentate ligands EXCEPT ____.

The iron obtained from the blast furnace contains significant impurities of carbon,phosphorus,and sulfur and is called ____.

Which of the following will not as a ligand to a transition metal cation?

What is the coordination number of the chromium in [Cr(phen) ₃]³⁺? The phen ligand is pictured below.Not all ligand lone pairs of electrons are explicitly shown.

The iron produced in a blast furnace contains significant impurities of carbon,phosphorus,and sulfur.These impurities are removed in a basic oxygen furnace,which converts the impurities to ________.

Ions such as [Co(H₂O) ₆]³⁺ and [Ag(CN) ₂]^- are called ____.

In which one of the following is the oxidation state of the underlined metal incorrect? Complex Ion Oxidation State of Underlined Metal

Most copper minerals are mined as ________.

In which of the following complexes does the transition metal have a d⁸ configuration?

The only compound containing copper in an ore is chalcopyrite,CuFeS₂.If a 91.0 g-sample of this ore contains 15.0 % of copper,what is the percentage of CuFeS₂ in the sample?