Questions and Answers of General Chemistry

Which contains greater entropy, a quantity of frozen benzene or the same quantity of liquid benzene at the same temperature? Explain in terms of the dispersal of energy in the substance.
When ammonia is first added to a solution of copper(II) nitrate, a pale blue precipitate of copper(II) hydroxide forms. As more ammonia is added, however, this precipitate dissolves. Describe what is
You are given a saturated solution of lead(II) chloride. Which one of the following solutions would be most effective in yielding a precipitate when added to the lead(II) chloride solution?a. 0.1 M
Suppose the Ka values for the hypothetical acids HX, HY, and HZ are 9.5 × 105, 7.6 × 104, and 1.2 × 102, respectively. Assuming that “A” is a cation that produces a slightly soluble salt
What is the molar solubility of calcium oxalate, CaC2O4, in a 0.203 M calcium chloride solution? The solubility product constant for calcium oxalate is 2.3 × 109.a. 4.8 × 105 Mb. 6.6 × 106 Mc.
Potassium superoxide,KO2, is often used in oxygen masks (such as those used by firefighters) because KO2 reacts with CO2 to release molecular oxygen. Experiments indicate that 2 mol of KO2 (s) react
Arrange the following oxides in order of increasing acidity: CO2, CaO,Al2O3, SO3, SiO2, and P2O5.
Discussing this chapter, a classmate says, “Since elements that form cations are metals and elements that form anions are nonmetals, elements that do not form ions are metalloids.”Do you agree or
How are metallic character and first ionization energy related?
Based on their positions in the periodic table, predict which atom of the following pairs will have the smaller first ionization energy:(a) Cl, Ar;(b) Be, Ca;(c) K, Co;(d) S, Ge;(e) Sn, Te.
Identify each statement as true or false. If it is false, rewrite it so that it is true:(a) Ionization energies are always negative quantitites.(b) Oxygen has a larger first ionization energy than
Write equations that show the process for(a) The first two ionization energies of lead and(b) The fourth ionization energy of zirconium.
Identify at least two ions that have the following ground-state electron configurations:(a) [Ar];(b) [Ar]3d5;(c) [Kr]5s24d10.
(a) What is an isoelectronic series?(b) Which neutral atom is isoelectronic with each of the following ions: Ga3+, Zr4+, Mn7+, I-, Pb2+?
Which of these spheres represents F, which represents Br, and which represents Br–?
The experimental Bi - I bond length in bismuth triiodide, BiI3, is 2.81 Å. Based on this value and data in Figure 7.6, predict the atomic radius of Bi. 1A H 2A 7A 8A 3A AA 5A 6A 0.37 Не 0.32 BCNOF
Estimate the As – I bond length from the data in Figure 7.6, and compare your value to the experimental As – I bond length in arsenic triiodide, AsI3, 2.55 Å. 1A H 2A 7A 8A 3A AA 5A 6A 0.37 Не
The prefix eka- comes from the Sanskrit word for “one.” Mendeleev used this prefix to indicate that the unknown element was one place away from the known element that followed the prefix. For
Which of the quantum numbers governs(a) The shape of an orbital,(b) The energy of an orbital,(c) The spin properties of the electron,(d) The spatial orientation of the orbital?
Identify the specific element that corresponds to each of the following electron configurations and indicate the number of unpaired electrons for each:(a) 1s22s2,(b) 1s22s22p4,(c) [A]4s13d5,(d) [Kr]
What is the maximum number of electrons in an atom that can have the following quantum numbers:(a) n = 2, ms = -1/2,(b) n = 5, l = 3,(c) n = 4, l = 3, m1 = 3;(d) n = 4, l = 0, m1 = 0?
Which of the following represent impossible combinations of n and l:(a) 1p,(b) 4s,(c) 5f,(d) 2d?
Which of the following represent impossible combinations of n and l:(a) 1p,(b) 4s,(c) 5f,(d) 2d?
Give the values for n, l, and ml for(a) Each orbital in the 2p subshell,(b) each orbital in the 5d subshell.
Give the numerical values of n and l corresponding to each of the following orbital designations:(a) 3p,(b) 2s,(c) 4f,(d) 5d.
Indicate whether energy is emitted or absorbed when the following electronic transitions occur in hydrogen:(a) From n = 2 to n = 6,(b) From an orbit of radius 4.76 Å to one of radius 0.529 Å,(c)
Indicate whether energy is emitted or absorbed when the following electronic transitions occur in hydrogen: (a) from n = 2 to n = 6,(b) From an orbit of radius 4.76 Å to one of radius 0.529 Å,(c)
Explain how the existence of line spectra is consistent with Bohr’s theory of quantized energies for the electron in the hydrogen atom.
List the following types of electromagnetic radiation in order of increasing wavelength:(a) The gamma rays produced by a radioactive nuclide used in medical imaging;(b) Radiation from an FM radio
What are the basic SI units for(a) The wavelength of light, (b) The frequency of light, (c) the speed of light?
Limestone stalactites and stalagmites are formed in caves by the following reaction:If 1 mol of CaCO3 forms at 298 K under 1 atm pressure, the reaction performs 2.47 kJ of P-V work, pushing back the
Because the oxide ion is basic, metal oxides react readily with acids.(a) Write the net ionic equation for the following reaction:(b) Based on the equation in part (a), write the net ionic equation
What does it mean to say that ions are solvated when an ionic substance dissolves in water?
When asked what causes electrolyte solutions to conduct electricity, a student responds that it is due to the movement of electrons through the solution. Is the student correct? If not, what is the
What parts of balanced chemical equations give information about the relative numbers of moles of reactants and products involved in a reaction?
(a) What is the mass, in grams, of a mole of 12C?(b) How many carbon atoms are present in a mole of 12C?
The following diagram represents the collection of CO2 and H2O molecules formed by complete combustion of a hydrocarbon. What is the empirical formula of the hydrocarbon?
Elements in the same group of the periodic table often form oxyanions with the same general formula. The anions are also named in a similar fashion. Based on these observations, suggest a chemical
Iodic acid has the molecular formula HIO3.Write the formulas for the following:(a) The iodate anion,(b) The periodate anion,(c) The hypoiodite anion,(d) Hypoiodous acid,(e) Periodic acid.
Give the names and charges of the cation and anion in each of the following compounds:(a) CaO,(b) Na2SO4,(c) KClO4,(d) Fe(NO3)2,(e) Cr(OH)3.
Selenium, an element required nutritionally in trace quantities, forms compounds analogous to sulfur. Name the following ions:(a) SeO42-(b) Se2‑(c) HSe-(d) HSeO3-
The most common charge associated with scandium in its compounds is 3+. Indicate the chemical formulas you would expect for compounds formed between scandium and(a) Iodine,(b) sulfur,(c) Nitrogen.
Using the periodic table to guide you, predict the chemical formula and name of the compound formed by the following elements:(a) Ga and F,(b) Li and H,(c) Al and I,(d) K and S.
Using the periodic table, predict the charges of the ions of the following elements:(a) Ga,(b) Sr,(c) As,(d) Br,(e) Se.
Each of the following elements is capable of forming an ion in chemical reactions. By referring to the periodic table, predict the charge of the most stable ion of each:(a) Mg,(b) Al,(c) K,(d) S,(e)
How many of the indicated atoms are represented by each chemical formula:(a) Carbon atoms in C2H5COOCH3,(b) Oxygen atoms in Ca(ClO4)2,(c) Hydrogen atoms in (NH4)2HPO4?
How many hydrogen atoms are in each of the following:(a) C2H5OH,(b) Ca(CH3COO)2,(c) (NH4)3PO4?
The elements of group 4A show an interesting change in properties moving down the group. Give the name and chemical symbol of each element in the group and label it as a nonmetal, metalloid, or metal.
Only two isotopes of copper occur naturally, 63Cu (atomic mass = 62.9296 amu; abundance 69.17%) and 63Cu (atomic mass = 64.9278 amu; abundance 30.83%). Calculate the atomic weight (average atomic
Write the correct symbol, with both superscript and subscript, for each of the following. Use the list of elements inside the front cover as needed:(a) The isotope of platinum that contains 118
Write the chemical formula for the following compound. Is the compound ionic or molecular? Name the compound. F F F F F
Four of the boxes in the following periodic table are colored. Which of these are metals and which are nonmetals? Which one is an alkaline earth metal? Which one is a noble gas?
You weigh an object on a balance and read the mass in grams according to the picture. How many significant figures are in this measurement? 2 1427 T. F Stanton 1000g
(a) The diameter of Earth at the equator is 7926.381 mi. Round this number to three significant figures, and express it in standard exponential notation.(b) The circumference of Earth through the
Indicate the number of significant figures in each of the following measured quantities:(a) 3.774 km,(b) 205 m2,(c) 1.700 cm,(d) 350.00 K,(e) 307.080 g,(f) 1.3 × 103 m/s.
What is the number of significant figures in each of the following measured quantities?(a) 601 kg,(b) 0.054 s,(c) 6.3050 cm,(d) 0.0105 L,(e) 7.0500 × 10-3 m3 ,(f) 400 g.
Indicate which of the following are exact numbers:(a) The mass of a 32-oz can of coffee,(b) The number of students in your chemistry class,(c) The temperature of the surface of the sun,(d) The mass
Indicate which of the following are exact numbers:(a) The mass of a piece of paper,(b) The volume of a cup of coffee,(c) The number of inches in a mile,(d) The number of ounces in a pound,(e) The
Label each of the following as either a physical process or a chemical process:(a) Rusting of a metal can,(b) Boiling a cup of water,(c) Pulverizing an aspirin,(d) Digesting a candy bar,(e) Exploding
Write the solubility product expression for the salt Ag3PO4.a. Ksp = 3[Ag+] × [PO43]b. Ksp = [Ag+][PO43]3c. Ksp = [Ag+]3[P3][O2]4d. Ksp = [Ag3+][PO4]3e. Ksp = [Ag+]3[PO43]
The solubility of the hypothetical salt A3B2 is 6.1 × 109 mol/L at a certain temperature. What is Ksp for the salt? A3B2 dissolves according to the equationa. 3.7 × 1017b. 9.1 × 1025c. 9.1 ×
How can you account for the fact that normal rain is slightly acidic?
If 20.0 mL of a 0.10 M NaOH solution is added to a 30.0- mL sample of a 0.10 M weak acid, HA, what is the pH of the resulting solution? (Ka = 1.8 × 105 for HA)a. 2.87b. 2.74c. 4.74d. 5.05e. 8.73
Hydrogen sulfide, H2S, is a very weak diprotic acid. In a 0.10 M solution of this acid, which of the following would you expect to find in the highest concentration?a. H2Sb. H3O+c. HSd. S2e. OH
If you mix 0.10 mol of NH3 and 0.10 mol of HCl in a bucket of water, you would expect the resulting solution to bea. Very basicb. Slightly basicc. Neutrald. Slightly acidice. Very acidic
Which of the following salts would produce the most basic aqueous solution?a. NaFb. KBrc. NH4Cld. MgCl2e. LiNO3
Which of the following is the weakest acid: HClO4, HCN, or HC2H3O2? See Table 15.1 and Table 16.1.TABLE 15.1Common Strong Acids and BasesStrong Acids ......................... Strong Bases*HClO4
What are the hydronium-ion and the hydroxide-ion concentrations of a solution at 25°C that is 0.0085 M barium hydroxide, Ba(OH)2?
A solution is 0.020 M HNO3 (nitric acid). What is the hydronium-ion concentration at 25°C? What is the hydroxideion concentration at 25°C?
In the following reaction of tetrafluoroboric acid, HBF4, with the acetate ion, C2H3O2, the formation of tetrafluoroborate ion, BF4, and acetic acid, HC2H3O2 is favored.HBF4 + C2H3O2 → BF4 +
In the following reaction of trichloroacetic acid, HC2Cl3O2, with formate ion, CHO2, the formation of trichloroacetate ion, C2Cl3O2, and formic acid, HCHO2 is favored.Which is the stronger acid,
Self-contained environments, such as that of a space station, require that the carbon dioxide exhaled by people be continuously removed. This can be done by passing the air over solid alkali
The pH of a solution is 9.55 at 25[1]C. What is the hydroxide-ion concentration in the solution?a. 2.8 × 1010 Mb. 3.5 × 105 Mc. 3.1 × 1010 Md. 3.2 × 105 Me. 3.8 × 105 M
Calculate the hydronium-ion concentration at 25°C in a 1.3 × 102 M Ba(OH)2 solution.a. 1.3 × 102 Mb. 7.7 × 1013 Mc. 2.6 × 102 Md. 3.8 × 1013 Me. 1.5 × 102 M
In the following reaction, identify the Lewis acid.a. CNb. Fe(CN)63c. H+d. Fe3+e. OH Fe+(aq) + 6CN (aq) = Fe(CN), (aq) 3-
The conjugate base of hydrofluoric acid dissolved in water is:a. Fb. OHc. H3O+d. HFe. F2
What is the sum of the pH and the pOH for a solution at 37°C, where Kw equals 2.5 × 1014?
Which is more acidic, a solution having a pH of 4 or one having a pH of 5?
The equilibrium constant Kc for the synthesis of methanol, CH3OH,CO(g) + 2H2(g) ⇌ CH3OH(g)is 4.3 at 250°C and 1.8 at 275°C. Is this reaction endothermic or exothermic?
The amount of nitrogen dioxide formed by dissociation of dinitrogen tetroxide,N2O4(g) ⇌ 2NO2(g) increases as the temperature rises. Is the dissociation of N2O4 endothermic or exothermic?
One way of preparing hydrogen is by the decomposition of water.2H2O(g) ⇌ 2H2(g) + O2(g); ΔH° = 484 kJWould you expect the decomposition to be favorable at high or low temperature? Explain.
Methanol is prepared industrially from synthesis gas (CO and H2).CO(g) + 2H2(g) ⇌ CH3OH(g); ΔH° = 21.7 kcalWould the fraction of methanol obtained at equilibrium be increased by raising the
Methanol is prepared industrially from synthesis gas (CO and H2).CO(g) + 2H2(g) ⇌ CH3OH(g); ΔH° = 21.7 kcalWould the fraction of methanol obtained at equilibrium be increased by raising the
Indicate whether either an increase or a decrease of pressure obtained by changing the volume would increase the amount of product in each of the following reactions.a. CO(g) + 2H2(g) ⇌ CH3OH(g)b.
(a) Predict the direction of reaction when chlorine gas is added to an equilibrium mixture of COCl2, CO, and Cl2. The reaction isCOCl2 (g) ⇌ CO(g) + Cl2(g)(b) What is the direction of reaction when
Consider the equilibriumFeO(s) + CO(g) ⇌ Fe(s) + CO2(g)When carbon dioxide is removed from the equilibrium mixture (say, by passing the gases through water to absorb CO2), what is the direction of
Would either of the following reactions go almost completely to product at equilibrium?a. 2NO(g) + 2H2(g) ⇌ N2(g) + 2H2O(g); Kc = 6.5 × 10113b. N2(g) + 2O2(g) ⇌ 2NO2(g); Kc = 3 × 1017
On the basis of the value of Kc, decide whether or not you expect nearly complete reaction at equilibrium for each of the following:a. N2(g) + O2(g) ⇌ 2NO(g); Kc = 4.6 × 1031b. C2H4(g)
The equilibrium-constant expression for a gas reaction isWrite the balanced chemical equation corresponding to this expression. Ke [C,Hg][O,]°
The equilibrium-constant expression for a gas reaction isWrite the balanced chemical equation corresponding to this expression. Ke [H,S]°[O2J°
An experimenter places the following concentrations of gases in a closed container: [NOBr] = 7.13 × 102 M, [NO] = 1.58 × 102 M, [Br2] = 1.29 × 102 M. These gases then react:2NOBr(g) ⇌ 2NO(g)
An experimenter places the following concentrations of gases in a closed container: [NOBr] = 7.13 × 102 M, [NO] = 1.58 × 102 M, [Br2] = 1.29 × 102 M. These gases then react:2NOBr(g) ⇌ 2NO(g)
A graduate student places 0.272 mol of PCl3(g) and 8.56 × 10-4 mol of PCl5(g) into a 0.718-L flask at a certain temperature.PCl5(g) is known to dissociate as follows:PCl5(g) ⇌ PCl3(g) +
The reaction 3A(g) +B(s) ⇌ 2C(aq) + D(aq) occurs at 25°C in a flask, which has 1.87 L available for gas. After the reaction attains equilibrium, the amounts (mol) or concentrations (M) of
A chemist put 1.18 mol of substance A and 2.85 mol of substance B into a 10.0-L flask, which she then closed. A and B react by the following equation:A(g) + 2B(g) ⇌ 3C(g) + D(g)She found that the
What is the rate law for the following gas-phase elementary reaction?2I + H2 → 2HI
Urea, (NH2)2CO, can be prepared by heating ammonium cyanate, NH4OCN.NH4OCN → (NH2)2COThis reaction may occur by the following mechanism:What is the rate law predicted by this mechanism? NH4 + OCN
Tertiary butyl chloride reacts in basic solution according to the equationThe accepted mechanism for this reaction isWhat should be the rate law for this reaction? (CH3);CCI + OH (CH3),COH + CI
Nitryl bromide, NO2Br, decomposes into nitrogen dioxide and bromine.A proposed mechanism isWrite the rate law predicted by this mechanism. 2NO,Br(g) → 2NO2(g) + Br2(g)
Methyl chloride, CH3Cl, reacts in basic solution to give methanol.This reaction is believed to occur in a single step. If so, what should be the rate law? CH3CI + OH CH,ОН + CI

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