Contrast the behavior of nitrogen and carbon by comparing the properties of:
a) methane and ammonia;
b) ethane and hydrazine
Difference in boiling points; different acid-base properties; difference in their combustions.
Why is dinitrogen very stable?
Yet why is dinitrogen not always the product during redox reactions involving nitrogen compounds.
a) Nitrogen has a very strong nitrogen-nitrogen triple bond.
b) Kinetic factors can lead to other products.
Nitrogen trifluoride boils at -129°C, whereas ammonia oils at -33°C. Account for the difference in these values.
Hydrogen bonding in ammonia molecules.
Draw the shape of each of the following molecules:
a) dinitrogen oxide;
b) dinitrogen tetroxide;
c) phosphorus trifluoride;
d) phosphonic acid.
Contrast the properties of the two common allotropes of phosphorus.
White phosphorus is a very reactive, white, waxy substance that consists of P4, while red phosphorus is a red powdery solid that consists of long polymer chains.
Suggest a structure for the O2F2 molecules, explaining your reasoning. Determine the oxidation number of oxygen in this compound and comment on it.
The oxidation number of +1 for oxygen is a result of each atom being sandwiched between a more electronegative fluorine atom.
Summarize the unique features of fluorine chemistry
Fluorine has a very weak fluorine-fluorine bond; its compounds with metals are often ionic when those of the comparable chlorides are covalent; it forms the strongest hydrogen bonds known; it tends to stabilize high oxidation states; the solubility of its metal compounds is often quite different than those of the other halides
Which of the folowing statements is false?
a) Chemical properties of group 15 elements are uniform.
b) Group 15 elements exhibit a wide range of oxidation states.
c) Group 15 elements form many compounds with oxygen.
White and black phosphorus are ___________ forms of the chemical element phosphorus.
Which of the following elements is used as a dopant in solid state devices?
Going down the group:
a. The +3 oxidation state becomes more favorable relative to the +5 one.
b. The +5 oxidation state becomes more favorable relative to the +3 one.
c. The +3 oxidation state predominates; the +5 one is rarely manifested.
The Haber-Bosch process, which has had a major impact on civilization, produces:
a. hydrazine, N2H4
b. ammonia, NH3
c. hydroxylamine, NHOH
PF3 is a ligand that is similar to CO in that:
a) It is a weak σ-donor and a weak π-acceptor.
b) It is a strong σ-donor and a strong π-acceptor.
c) It is a weak σ-donor and a strong π-acceptor.
The synthesis of organophosphorus compounds includes:
a) rapidly oxidized by O2 to NO2 in the atmosphere.
b) an odd electron molecule.
c) not an atmospheric pollutant.
When heated above 200°C, phosphoric acid, H3PO4:
a) forms polyphosphates by condensation
b) decomposes thermally
c) releases P2O5
Select the correct answer:
a. Organometallic compounds of group 15 elements in +3 oxidation state become less stable in the order Bi >
Sb > As. Aryl compounds are more stable than alkyls.
b. Organometallic compounds of group 15 elements in +3 oxidation state become less stable in the order As >
Sb > Bi. Aryl compounds are more stable than alkyls.
c. Organometallic compounds of group 15 elements in +3 oxidation state become less stable in the order As >
Sb > Bi. Aryl compounds are less stable than alkyls.
The electron configuration of group 16 elements is ns2np4. This configuration suggests.
a. a maximum oxidation number of +6
b. a maximum oxidation number of +4
c. a maximum oxidation number of –2
Sulfur-containing impurities that are naturally present in crude oil and natural gas are removed by:
a. fractional distillation
b. the Frasch process
c. the Claus process
Water can be viewed as a hydride of oxygen. By comparison with the heavier hydrides in the group, water's melting and boiling points are higher than expected because:
a. The water molecules have the lowest bond length of all group 16 hydrides.
b. The water molecules form hydrogen bonds to a much higher degree than the remaining group 16 hydrides.
c. The water molecules have the highest bond angles of all group 16 hydrides.
The geometry of the SF4 molecule is:
b. triagonal planar
Identify the free radical chain reaction that produce acid rain in the atmosphere:
Select the correct statement about the oxoanions of sulfur:
a) SO32- is a strong oxidizing agent; SO42- is a strong reducing agent; S2O82- is unreactive.
b) SO32- is a strong reducing agent; SO42- is a strong oxidizing agent; S2O82- is unreactive.
c) SO32- is a strong reducing agent; SO42- is unreactive; S2O82- is a strong oxidizing agent.
Diatomic oxygen readily removes electrons from metals to form a variety of metal oxides. In general:
a) Oxides of M2+ ions (MO formula) have a rock salt structure (6:6 coordination).
b) Oxides of M3+ ions (M2O3 formula) have a fluorite structure (6:3 and 8:4 coordination).
c) Oxides with an MO4 formula have a 6:4 coordination.
S, Se, and Te form polyanions as follows:
a. S forms chains and bicyclic ring polysulfides.
b. Se forms chain and ring polyselenides.
c. Te forms chain polytellurides only.
In the case of oxoacids of sulfur:
a. Sulfuric acid decomposes but forms stable salts.
b. Thiosulfuric acid is a strong acid.
c. Sulfurous acid is actually an aqueous solution of SO2.
a) decompose explosively
b) are stable
c) do not exist
The halogens have high electron affinity because:
a. They can accommodate only one electron in their valence shell; therefore the energy required for this process is low.
b. The incoming electron can occupy an orbital of an incomplete valence shell and thus experience strong nuclear attraction.
c. The nuclear attraction to the electrons in their atoms is high and tends to draw new electrons in.
All group 17 elements:
a. undergo thermal or photochemical dissociation in the gas phase to form free radicals
b. are gases at room temperature
c. sublimate easily
Why are aqueous fluoride solutions not used in the production of fluorine by electrolysis?
a. because fluorides are insoluble in water.
b. because water is oxidized at a much lower potential than F- and because any F2 produced would react rapidly with the water.
c. because the electrolysis of water solutions of fluorides would require a prohibitively large amount of water and energy.
Fluorine atoms are small and their electrons are tightly gripped by the nucleus. Therefore, molecular fluorine compounds have:
a. high polarizabilities and strong dispersion interactions.
b. low polarizabilities and strong dispersion interactions.
c. low polarizabilities and weak dispersion interactions.
What is the molecular (electron-domain) geometry of ClF3 as predicted by VSEPR?
a. trigonal bipyramidal
b. trigonal pyramidal
c. trigonal planar
When I2 is added to a solution containing I-, a deep brown color develops. How can that phenomenon be explained?
a) I- is oxidized to I2.
b) I2 is dissolved in the water.
c) Polyiodides, such as I3- and I5-, are formed.
Perchlorate is a very weak Brønsted base and a weak Lewis base and is used as a weakly coordinating ion that can be easily displaced from a complex by other ligands. When using the perchlorate ion in this situation, care must be taken because:
a. The perchlorate ion is a powerful oxidizing agent that can explode unexpectedly and unpredictably.
b. The perchlorate ion is a powerful oxidizing agent that rapidly oxidizes the ligands before complexes are formed for further study.
c. The perchlorate ion is a powerful oxidizing agent that rapidly oxidizes the metal acceptors before complexes are formed for further study.
Basic solutions of chlorine, bromine, and iodine undergo _____, with the formation of +1 (XO-) and –1 (X-) species:
The oxidation of molecules and ions by halogen oxoanions increases in the order:
a) ClO2-< ClO3-< ClO4-
b) ClO4-< BrO4-< IO4-
c) IO3-< IO4-
Why must care be taken during the high-temperature depolymerization of polytetrafluoroethylene (PTFE)?
a. because the monomer, tetrafluoroethylene, is highly toxic
b. because a byproduct, perfluoroisobutylene, is highly toxic
c. because PTFE decomposes explosively at high temperatures
The inert gases possess an electron configuration of ns2np6. Which statement applies to their ionization energy and electron affinity?
a. low ionization energies and negative electron affinities
b. high ionization energies and negative electron affinities
c. low ionization energies and positive electron affinities
Which noble gas seems to defy the notion that group 18 elements are chemically inert?
Which of the noble gases is classified as an indoor air pollutant?
c) No inert gas is an air pollutant
Xe forms _________ with fluorine.
a) XeF2 and XeF4.
b) XeF2, XeF4, and XeF6.
c) no compounds.
a) are strong reducing agents.
b) form complexes with F2.
c) form complexes with F-.
Xe fluorides are of interest because:
a. They can be used to prepare noble gas compounds with elements other than fluorine and oxygen.
b. The molecular shape of their complexes with fluoride ions is unknown; more research needs to be done.
c. They are the only compounds of Xe.
Xe oxides can be prepared by direct interaction of the element with oxygen.
a. This statement is correct.
b. This statement is incorrect.
c. Only XeO3 can be prepared that way; XeOF2 and XeOF4 cannot.
Organoxenon compounds can be prepared by:
a. direct interaction between an aromatic hydrocarbon and Xe
b. hydrolysis of phenol in the presence of a Xe fluoride
The stability of the complexes M(CO)5E (where M = Cr, Mo, or W and E = Ar, Kr, or Xe) decreases in the order:
a. W > Mo ≈ Cr and Xe > Kr > Ar
b. Cr > Mo ≈ W and Xe > Kr > Ar
c. Cr > Mo ≈ W and Ar > Kr > Xe
Which statement is correct?
a. Like Xe, Kr and Rn form fluorides and oxides.
b. Kr and Rn can form fluorides but in a more limited fashion than Xe.