Question 1

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 given configuration has dS1U1P18S1S1P0 which means there are 1 electron in the s-orbital, 1 in the p-orbital, 18 in the d-orbital and another s-orbital with 1 electron. Among the given options, only PtClS1U1B14S1U1B0S1U1P12-S1S1P0 has Platinum (Pt) which has atomic number 78 and configuration [Xe]4f14 5d9 6s1. This means that in its ground state, Pt has 1 electron in s-orbital, 1 in p-orbital, 9 in d-orbital and 1 in 6s-orbital. When a chloride ion (Cl-) and 14 ethylenediamine (en) molecules (S1U1B14S1U1B0) coordinate with Pt, they form the complex PtClS1U1B14S1U1B0S1U1P12-S1S1P0. In this complex, 1 electron from 6s-orbital will shift to the vacant 5d-orbital, hence forming a dS1U1P13S1U1P12 configuration. The total number of electrons in the d-orbital will be 13, along with 1 electron in the s-orbital, 1 in the p-orbital and another s-orbital with 1 electron, which matches the given configuration. Therefore, the correct answer is D.

Question 2

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

The process of enriching copper ores by increasing the percentage of copper is called flotation. In this process, the ore is mixed with water and chemicals, and air is pumped through the mixture. This creates bubbles that attach to the copper particles, causing them to rise to the surface and form a froth that can be skimmed off. This froth is then dried and heated to remove excess water and concentrate the copper content.

Question 3

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 4

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 is determined by the number of ligands directly bonded to the central metal ion. In this complex, there are six ligands bonded to the Cu(II) ion (four sulfur atoms from the NH₃ ligand and two nitrogen atoms from the imidazole group of the same ligand). Therefore, the coordination number is six.

Question 5

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 6

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 cannot act as a polydentate ligand because it only has one N atom available to coordinate with a metal ion. All of the other choices have multiple donor atoms available for coordination.

Question 7

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 and carbon monoxide react with iron(III) oxide in the blast furnace to reduce it to impure iron. This is the process known as smelting. Hydrogen, chlorine, calcium silicate, calcium oxide, and carbon dioxide are not involved in this process.

Question 8

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

The ions given are examples of coordination complexes, which are composed of a central metal ion or atom bonded to multiple surrounding ligands. Therefore, choice E, coordination complexes, is the best answer. Choices A and B (ligands and Lewis bases) are both components of coordination complexes, but do not encompass the entire structure. Choice C (chelates) is a type of coordination complex where a ligand forms multiple bonds with a central metal ion, but not all coordination complexes are chelates. Choice D (alloys) refers to a mixture of two or more metallic elements, which is not relevant in this context.

Question 9

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

Accepted Answer

Most copper minerals are mined as sulfides, such as chalcopyrite (CuFeS2) and bornite (Cu5FeS4).

Question 10

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

Tempering is a process that involves reheating previously hardened or quenched steel to a temperature below its melting point, and then allowing it to cool. This process changes the microstructure of the steel, which affects its properties such as flexibility, strength, hardness, and malleability.

Question 11

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 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, which contains impurities of carbon, phosphorus, and sulfur, is called pig iron. This form of iron is not yet useful for most commercial purposes and needs to be further processed to remove the impurities before it can be turned into steel or cast iron.

Question 13

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 answer of What is the coordination number of the...

Question 14

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 15

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 not found in nature as a free element - it typically occurs in minerals such as ilmenite and rutile. However, iridium, gold, platinum, and rhodium are all found in nature as free elements.

Question 16

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 17

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)

Question 18

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 often found in its native state, rather than as an oxide or sulfide.

Question 19

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

The answer of When 7.9 moles of [Co(NH₃)₅Cl]Cl₂ is dissolved...

Question 20

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

The answer of The iron produced in a blast furnace...

Quiz 23: The Chemistry of the Transition Elements

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

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

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

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

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

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

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

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

Most copper minerals are mined as ________.

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

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

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

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.

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

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 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?

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?

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 ________.