The molten layer of calcium silicate and other impurities that floats on top of the molten iron in a blast furnace is called slag.
Missing Word
slag
Slag is the waste layer formed when impurities in an ore combine with an added substance such as limestone. Because it is less dense, it floats on the iron and also shields the iron from oxidation.
Category: Metal Production
Question 2
Coal that has been heated without air to drive off its volatile components, used as both fuel and reducing agent in a blast furnace, is called coke.
Missing Word
coke
Coke is nearly pure carbon made by heating coal in the absence of air. In the furnace it burns to supply heat and forms carbon monoxide, which reduces the iron ore.
Category: Metal Production
Question 3
A substance such as limestone that is added during smelting to combine with impurities and carry them away is called a flux.
Missing Word
flux
A flux reacts with impurities such as silica to form a molten waste that separates from the metal. Limestone is the common flux in iron and copper smelting.
Category: Metal Production
Question 4
Heating a sulfide ore of copper strongly in air, which converts some of its sulfur into sulfur dioxide, is called roasting.
Missing Word
roasting
Roasting is a preliminary treatment that heats an ore in air to convert sulfides toward oxides and drive off sulfur as SO2. It prepares the ore for smelting.
Category: Metal Production
Question 5
The molecules or ions that donate electron pairs to the central metal atom in a coordination complex are called ligands.
Missing Word
ligands
Ligands are Lewis bases bonded to a central metal ion through donor atoms that each supply an electron pair. Examples include water, ammonia, chloride and cyanide.
Category: Complex Structure
Question 6
A ring structure formed when a single ligand bonds to a metal through two or more donor atoms is called a chelate.
Missing Word
chelate
A chelate forms when a polydentate ligand grips a metal at more than one point, like a claw. Chelates such as those made by EDTA are especially stable.
Category: Complex Structure
Question 7
When water acts as a ligand, it is given the name aqua in the name of a complex.
Missing Word
aqua
Aqua is the special ligand name for H2O, as in hexaaquairon(II). Other neutral ligands with special names include ammine for NH3 and carbonyl for CO.
Category: Naming Complexes
Question 8
When a carbon monoxide molecule is bonded to a metal as a ligand, it is named carbonyl.
Missing Word
carbonyl
Carbonyl is the ligand name for CO, which bonds to metals through its carbon atom. Nickel tetracarbonyl, Ni(CO)4, is a classic example.
Category: Naming Complexes
Question 9
A complex with coordination number 6 almost always has an octahedral geometry.
Missing Word
octahedral
Six donor atoms arranged at the corners of an octahedron place every pair of neighboring ligands 90 degrees apart. This is the most familiar shape for transition metal complexes such as [Co(H2O)6]2+.
Category: Complex Structure
Question 10
The green plant pigment chlorophyll is a coordination complex built around an ion of the element magnesium.
Missing Word
magnesium
Chlorophyll contains a Mg2+ ion held by four nitrogen atoms of a ring-shaped ligand similar to heme. The complex absorbs red and blue light for photosynthesis.
Category: Complexes in Nature
Question 11
The halogen that brings transition metals to their highest oxidation states when it forms halides with them is fluorine.
Missing Word
fluorine
Fluorine is the most electronegative and most strongly oxidizing halogen, so transition metal fluorides show higher oxidation states than the corresponding chlorides, bromides or iodides.
Category: Transition Metal Properties
Question 12
A ranking of ligand types from those causing the smallest d orbital splitting to those causing the largest is called the spectrochemical series.
Missing Word
spectrochemical
The spectrochemical series orders ligands by field strength, from weak-field halides such as iodide to strong-field ligands such as cyanide. It predicts whether a complex will be high spin or low spin.
Category: Crystal Field Theory
Question 13
A substance with no unpaired electrons is slightly repelled by a magnetic field and is described as diamagnetic.
Missing Word
diamagnetic
Diamagnetic substances have all their electrons paired, so they have no net magnetic moment and are weakly pushed out of a magnetic field. Low-spin d6 complexes such as [Fe(CN)6]4- are examples.
Category: Color and Magnetism
Question 14
The color seen for a complex is the complementary color of the light it absorbs.
Missing Word
complementary
Complementary colors lie opposite each other on a color wheel. A complex that absorbs red light, for example, transmits the remaining wavelengths and appears green.
Category: Color and Magnetism
Question 15
A Co3+ ion has 6 electrons in its 3d subshell.
Missing Word
6
Cobalt has the configuration [Ar]4s2 3d7. Losing the two 4s electrons and one 3d electron to form Co3+ leaves 6 electrons in the 3d subshell, making it a d6 ion.
Category: Crystal Field Theory