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Sodium metal with water
2Na + 2H2O ----> 2NaOH + H2
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Rubidium metal with dioxygen
Rb + O2 ----> RbO2
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Solid potassium hydroxide with carbon dioxide
2KOH + CO ----> K2CO3 + H2O
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Heating solid sodium nitrate
2NaNO3 ----> 2NaNO2 + O2
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Heating calcium in dioxygen
2Ca + O2 ----> 2CaO
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Heating calcium carbonate
CaCO3 ----> CaCO + O2
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Evaporating a solution of Calcium Hydrogen carbonate
Ca(HCO3)2 ----> CaCO3 + CO2 + H2O
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Heating calcium oxide with carbon
CaO + 3C ----> CaC2 + CO
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Liquid potassium metal with solid aluminum chloride
3K + AlCl3 ----> 3KCl + Al
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Solid diboron trioxide with ammonia gas at high temperature
B2O3 + 2NH3 ----> 2BN + 3H2O
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Aluminum metal with hydroxide ion
2Al + 2OH- + 6H2O ----> 2[Al(OH)4] + 3H2
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Tetraborane, B4H10, and dioxygen
2B4H10 + 11O2 ----> 4B2O3 + 10H2O
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Solid lithium dicarbide (2-) with water
Li2C2 + 2H2O ----> 2LiOH + C2H2
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Silicon dioxide with carbon
SiO2 + 2C ----> Si + 2CO
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Copper (II) oxide heated with carbon monoxide
CuO + CO ----> Cu + CO2
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Calcium hydroxide solution with carbon dioxide
- Ca(OH)2 + CO2 ----> CaCO3 + H2O
- CaCO3 + CO2 + H2O ----> Ca(HCO3)2
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Methane with molten sulfur
CH4 + 4S ----> CS2 + 2H2S
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Silicon dioxide with molten sodium carbonate
SiO2 + 2Na2CO3 ----> Na2SiO4 + 2CO2
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Lead (IV) oxide with concentrated hydrochloric acid
- PbO2 + 4HCl ----> PbCl4 + 2H2O
- PbCl4 ----> PbCl2 + Cl2
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In what way do the alkali metals resemble "typical" metals? In what ways are they very different?
They resemble “typical” metals in that they are shiny and silvery and good conductors of heat and electricity. The alkali metals differ from “typical” metals in that they are soft, extremely chemically reactive, have low melting points and very low densities.
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Describe three of the common features of the chemistry of the alkali metals.
All common chemical compounds are water soluble. They always form ions of +1 oxidation state. Their compounds are almost always ionic.
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Several of the alkali metal compounds have common names. Give the systematic name corresponding to (a) casutic soda; (b) soda ash; (c) washing soda.
- (a) Sodium hydroxide;
- (b) anhydrous sodium carbonate;
- (c) sodium carbonate decahydrate.
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Explain briefly why the ammonium ion is often referred to as pseudo-alkali metal.
The ammonium ion is monopositive; its salts are all soluble; its size is about the middle of the alkali metal ion range; all its common salts are colorless.
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Explain why entropy factor favor the solution of sodium chloride but not that of magnesium chloride
The higher charge density magnesium ion will cause the water molecules surrounding it during the hydration step to become much more ordered than with the lower charge density sodium ion.
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What are the two most important common features of the Group 2 elements?
They form 2+ ions exclusively and their salts tend to be highly hydrated.
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Several of the alkaline earth metal compounds have common names. Give the systematic name for (a) dolomite; (b) milk of magnesia; (c) Epsom salts.
- (a) CaCO3 • MgCO3;
- (b) Mg(OH)2;
- (c) MgSO4 • 7 H2O.
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Discuss briefly the similarities between beryllium and aluminum.
Both form tough oxide coatings over their surface; they are amphoteric, forming beryllate and aluminate anions; they form carbides containing the C4− ion.
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Describe and write corresponding chemical equations showing how you would prepare from magnesium metal each of the following: (a) magnesium chloride monohydrate; (b) anhydrous magnesium chloride.
- (a) Mg + 2HCl ----> MgCl2 + H2
- then evaporate to crystallize MgCl2·H2O.
- (b) Mg + Cl2 Mg ---->Cl2
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The common hydrate of magnesium sulfate is the heptahydrate, MgSO4(7H2O). In the crystal structure, how many water molecules are likely to be associated with the cation? with the anion?
The formula is actually [Mg(OH2)6]2+[SO4·H2O]2−
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Which of the following gaseous species should be the most stable: BeH, BeH+, or BeH-? Show your reasoning?
BeH+. This ion would possess a single bond.
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With a very high charge density, aluminum would not be expected to exist widely as a free 3+ ion, yet it does exist in the form of a hydrated 3+ ion. Explain why.
Al3+ is surrounded by the partially negative oxygen atoms of the six water molecules.
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Explain briefly why solutions of aluminum chloride are strongly acidic.
The hydrated aluminum ion acts as a Bronsted-Lowry acid.
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Contrast the bonding in the different aluminum halides.
Aluminum fluoride is a typical ionic compound. Both aluminum bromide and aluminum iodide are covalently bonded dimers. Aluminum chloride is a borderline case.
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The metallic, covalent, and ionic (six-coordinate) radii for aluminum are 143pm, 130 pm, and 54pm. Explain why these values are different.
The metallic radius is a measure of the atomic size. The covalent radius will be smaller because there is orbital overlap. The ionic radius is by far the smallest because all the valence electrons have been lost.
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When aluminum chloride is dissolve in benzene, C6H6, a dimer, Al2Cl6 is obtained. However, when the compound is dissolved in diethylether, (C2H5)2O, a chemical reaction occurs to give species containing one aluminum atom. Suggest the identity of the compound.
Cl3Al[O(C2H5)2].
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A solution of beryllium ion, [Be(OH2)4]2+ (aq), is strongly acidic. Write a balanced chemical equation for the first step in the process. Explain why you would expect this ion to be acidic. The beryllium ion will resemble the aluminum ion.
- The beryllium ion will resemble the aluminum ion.
- [Be(OH2)4]2+ + H2O ----> [Be(OH2)3(OH)]+ + H3O+
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When gallium (III) salts are dissolved in water, the [Ga(OH2)6]3+ (aq) ion is initially formed, but a white precipitate of GaO(OH) slowly forms. Write a blanced chemical equation for the process and suggest how the gallium (III) ion can be kept in solution.
- Ga(OH2)63+ ----> GaO(OH) + H2O + 3H3O+
- Addition of acid will shift the equilibrium to the left.
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Contrast the properties of the three main allotropes of carbon-diamond, graphite, and C60.
Diamond is a very hard, transparent, colorless solid that is a good conductor of heat but a non-conductor of electricity. Graphite is a soft, slippery, black solid that is a poor conductor of heat but a good conductor of electricity. C60 is black and a nonconductor of heat and electricity.
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Why are fullerness soluble in many solvents even though both graphite and diamond are insoluble in all solvents?
Diamond and graphite both have network covalent bonded structures. The solvation process cannot provide the energy necessary to break nonpolar covalent bonds. The fullerenes consist of discrete molecules, such as C60. These individual nonpolar units can become solvated by nonpolar or low-polarity solvent molecules and hence dissolve.
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Construct the electron-dot structures of tin (IV) chloride and gaseous tin (II) chloride. Draw the corresponding molecular shapes.
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Write the formulas of two carbon-containing species that are isoelectronic with the C22- ion.
CN− and CO.
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There is a trimeric silicate ion, Si3O96-: (a) draw a probable structure for the ion; (b) phosphorus forms an isoelectronic and isostructural ion. What would be its formula? (c) Another element forms an isoelectronic and isostructural neutral compound. What would be its formula?
- (a) A six-membered ring structure, Si3O3, with alternating silicon and oxygen atoms.
- (b) P3O93−
- (c) S3O9.
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In the following reaction, identify which is the Lewis acid and which is the Lewis base. Give your reasoning.
- Cl- + SnCl2 ----> SnCl3-
- Tin(II) chloride is the Lewis acid, while the chloride ion, the Lewis base.
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The metals from group 1 are different from other metals in that:
- a) They have low densities and are very reactive.
- b) They have low densities and are not very reactive.
- c) They have high densities and are very reactive.
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Electrolysis is used for the production of:
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All of the following statements are correct except:
- a) Group 1 elements are poor complexing agents.
- b) Group 1 elements are strong complexing agents.
- c) Group 1 elements are strong reducing agents.
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Select the expected correct order of arrangement of group 1 halides according to their increasing stability:
- a) CsF < RbF < KF < NaF < LiF
- b) LiF < NaF < KF < RbF < CsF
- c) LiF < LiCl < LiBr < LiI
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Only _____________ forms a normal oxide in direct reaction with O2.
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Which statement is correct about group 1?
- a) All group 1 carbonates, except that of Li, are soluble in water.
- b) All group 1 carbonates, except that of Li, decompose significantly when heated.
- c) Sodium carbonate is produced by the Solvay process.
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Lithium, like group 2's magnesiu, forms a nitride by direct reaction with nitrogen. The two reactions are displays of a:
- a) diagonal relationship
- b) interperiod relationship
- c) intergroup relationship
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Which of the listed oxosalts of sodium is used as fertilizer?
- a) Na2SO4
- b) NaNO3
- c) Na2CO3
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Group 1 metal ions are hard Lewis acids. Therefore, their interactions with Lewis bases are predominantly:
- a) covalent
- b) electrostatic
- c) metallic
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Transmetallation reactions involve:
- a) breaking metal-carbon bonds and forming new metal-carbon bonds but with a different metal
- b) breaking metal-carbon bonds and forming metal-metal and carbon-carbon bonds
- c) breaking metal-carbon bonds and forming carbon-carbon bonds and elemental metal
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The ionization energies of group 2 elements decrease and the radii decrease down the group. Therefore:
- a) The metals are less easily oxidized down the group.
- b) The metals are mosre easily oxidized down the group.
- c) Redox properties do not change systematically down the group.
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Which of the following statements is correct?
- a) Be is resistant to corrosion and can be used in specialized alloys and as a moderator for nuclear reactions.
- b) Mg is of great biological importance since it is the acceptor component in the hemoglobin molecule.
- c) Ca is used in pyrotechnics and in classes for color TV tubes.
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Which group 2 elements does not form saline hydride?
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Select the incorrect statement:
- a) Be forms covalent halides.
- b) All group 2 halides, except the fluorides of Mg, Ca, Sr, and Ra, are soluble in water.
- c) All fluorides of group 2 elements are insoluble in water.
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Are all group 2 peroxides strong oxidizing agents?
- a) Yes.
- b) No.
- c) All are, except BaO2.
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What is the pH of a saturated solution of Ca(OH)2? The solubility of Ca(OH)2 is 2.111 x 10-3 M.
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Group 2 carbides react with water to produce:
- a) CO gas
- b) H2 gas
- c) hydrocarbon gas
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Are all group 2 carbonates solube in water?
- a) All are sparingly soluble, except BeCO3.
- b) All are sparingly soluble in water.
- c) All are sparingly soluble, except CaCO3.
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Do all group 2 elements form stable complexes with simple ligands?
- a) Only Ca does.
- b) Only Be does.
- c) None of them does.
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Which of the listed groups of compounds are Grignard reagents?
- a) alkyl- and arylberylllium compounds.
- b) alkyl- and arylmagnesium halides.
- c) alkyl- and arylcalcium compounds.
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What is the difference between boron and the remaining elements from group 12?
- a) Boron is nonmetallic; all remaining elements are distinctly metallic.
- b) There is no difference; all elements are metallic.
- c) There is no difference; all elements are nonmetallic.
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Boron and group 14's silicon have similar properties. This phenomenon is called:
- a) a diagonal relationship
- b) an intergroup relationship
- c) an interperiodic relationship
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Which statement is incorrect?
- a) Boranes are binary hydrogen compounds of boron.
- b) All boranes are flammable.
- c) No boranes undergo hydrolysis.
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Boron thalides are:
- a) weak Lewis acids
- b) strong Lewis acids
- c) strong Lewis bases
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The anion of H3BO3 in concentrated neutral or basic solutions:
- a) is a very weak Brønsted-Lowry base.
- b) is a very weak Brønsted-Lowry acid.
- c) polymerizes by condensation.
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Compounds containing B-N bonds are isoelectric with compounds containing:
- a) C-N bonds
- b) C-C bonds
- c) B-B bonds
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How many skeletal electrons are there in B5H9?
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Alkyl aluminum halides are:
- a) molecular compounds that are used to couple alkenes.
- b) ionic compounds that are used to couple alkenes.
- c) coordinate compounds that are used to couple alkenes.
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The stability of group 13 monohalides increases with:
- a) increasing Z in the group.
- b) decreasing Z in the group.
- c) The stability of group 13 monohalides does not change with Z.
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Which is correct about GaAs?
- a) GaAs has lower electron mobility and more electronic noise than silicon; GaAs decomposes in moist air.
- b) GaAs has higher electron mobility and less electronic noise than silicon; GaAs decomposes in moist air.
- c) GaAs has higher electron mobility and less electronic noise than silicon; GaAs is stable in moist air.
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All group 13 elements except ___________ exist as several allotropes.
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Partially crystalline forms of carbon include:
- a) diamonds
- b) carbon clusters
- c) activated carbon
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Compared to hydrocarbons, silanes are:
- a) more reactive
- b) less reactive
- c) just as reactive
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The thermal stability of germane, stanane, and plumbane decreases in the following order:
- a) There is no appreciable difference in the thermal stability of germane, stanane, and plumbane.
- b) GeH2 > SnH2 > PbH2c) PbH2 > SnH2 > GeH2
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Which statement is incorrect?
- a) CO is as strong reducing agent.
- b) CO is an excellent ligand toward metals in low oxidation states.
- c) CO reacts with OH- to form CH3COO-.
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The cyclic anion [Si3O9]n- has a __________ structure and a charge of _________?
- a) three-atomic ring; -6.
- b) six-atomic ring; -6.
- c) nine-atomic ring; -6.
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The cyanide ion, CN-, is:
- a) isoelectronic with the CO2 molecule.
- b) a weak Brønsted base.
c) highly poisonous.
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Molecular sieves are:
- a) crystalline alumosilicates that have open structures with apertures of molecular sizes.
- b) soccer-ball-shaped cluster compounds consisting of carbon atoms.
- c) concentric cylindrical tubes formed of sheets containing hexagonal arangements of carbon atoms.
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Silicon polymers can be synthesized in liquid, gel, or resin forms, which, just like their properties, depend on:
- a) the length of the polymeric chain.
- b) the degree of polymerization and cross-linking of the polymer chains.
- c) the degree of branching of the polymer chains.
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Unlike organosilicon and organogermanium compounds, the organotin compounds are characterized by:
- a) greater occurrence of the +2 oxidation state, greater range of coordination numbers, and the presence of halide bridges.
- b) greater occurrence of the +4 oxidation state, greater range of coordination numbers, and hte presence of halide bridges.
- c) greater occurrence of the +4 oxidation state, lower range of coordination numbers, and the presence of halide bridges.
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