Questions and Answers of General Chemistry

The highest melting point for metals in the fifth period occurs for molybdenum. Explain why this is expected.
According to the building-up principle, what is the electron configuration of the ground state of the technetium atom (atomic number 43)?
A solution of chlorous acid may be prepared by reacting a solution of barium chlorite with sulfuric acid. Barium sulfate precipitates. Write the balanced equation for the reaction.
solution of chloric acid may be prepared by reacting a solution of barium chlorate with sulfuric acid. Barium sulfate precipitates. Write the balanced equation for the reaction.
Sodium thiosulfate, Na2S2O3, is prepared from sodium sulfite and sulfur:8Na2SO3(aq) + S8(s) → 8Na2S2O3(aq)How many grams of Na2S2O3 can be obtained from 50.0 g of sulfur?
Use balanced equations to show how you could prepare methanol, CH3OH, from ethane, C2H6, and water.
Use balanced equations to show how you could prepare Na2CO3 from carbon, NaOH, air, and H2O.
Complete and balance the following equations.a. NaHCO3(aq) + HC2H3O2(aq) →b. Ca(HCO3)2(aq) + Ca(OH)2(aq) →
Complete and balance the following equations.a. CO2(g) + Ba(OH)2(aq) →b. MgCO3(s) + HBr(aq) →
Lead(II) nitrate, one of the few soluble lead salts, gives a solution with a pH of about 3 to 4. Write a chemical equation to explain why the solution is acidic.
The Sn2+(aq) ion can be written in more detail as Sn(H2O)62+. This ion is acidic by hydrolysis. Write a possible equation for this hydrolysis.
Baking powders contain sodium (or potassium) hydrogen carbonate and an acidic substance. When water is added to a baking powder, carbon dioxide is released. One kind of baking powder contains NaHCO3
A short-lived isotope of radium decays by alpha emission to radon-219. Write the nuclear equation for this decay process.
Thorium-230, which occurs in uranium minerals, decays by alpha emission to radium. Write the nuclear equation for this decay process.
Devise a chemical method for separating a solution containing NaCl and MgCl2 to give two solutions or compounds each containing only one of the metal ions.
Devise a chemical method for separating a solution containing MgCl2 and BaCl2 to give two solutions or compounds each containing only one of the metal ions.
Potassium hydroxide and barium hydroxide are strong bases. What simple chemical test could you use to distinguish between solutions of these two bases?
Sodium hydroxide and calcium hydroxide are strong bases. What simple chemical test could you use to distinguish between solutions of these two bases?
Francium-223 is a radioactive alkali metal that decays by beta emission. Write the nuclear equation for this decay process.
Francium was discovered as a minor decay product of actinium-227. Write the nuclear equation for the decay of actinium-227 by alpha emission.
Manganese is available from its ore pyrolusite, which is manganese(IV) oxide, MnO2. Some manganese metal is prepared from MnO2 by reduction with aluminum metal. Write the balanced equation for this
Pure iron is prepared for special purposes by precipitating iron(III) oxide and reducing the dry oxide with hydrogen gas. Write the balanced equation for this reduction of iron(III) oxide.
Hydrogen chloride can be prepared by heating NaCl with concentrated sulfuric acid. Why is substituting NaBr for NaCl in this reaction not a satisfactory way to prepare HBr?
Given that the reaction Cl2(g) + 2KBr(aq) → 2KCl(aq) + Br2(aq) readily occurs, would you expect the reaction I2(s) +2KCl(aq) → 2KI(aq) + Cl2(aq) to occur?
Tin metal would not make a very good structural metal in cold climates. Why?
What happens to the metallic character of the main-group elements as you move left to right across any row of the periodic table? What happens to the metallic character of the main-group elements as
Even though hydrogen isn’t a metal, why is it in Group IA of most periodic tables?
When producing coke, why is the coal heated in the absence of air? Write the chemical reaction for what would happen if it were to be heated in air.
Sodium hypochlorite is used in laundry bleach. The formula of sodium hypochlorite isa. NaClb. NaClOc. NaClO2d. NaClO3e. NaClO4
The major use of Ca3(PO4)2 is ina. The tempering of metalsb. Phosphorus for fireworksc. Acid neutralizationd. The production of phosphoric acide. The vulcanization of rubber
In which of the following is nitrogen or nitrogen-containing compounds not used?a. Fertilizerb. Explosivesc. Dental anestheticd. Blanketing gase. Jet fuel
Which of the following are used in the production of H2(g)?I. steam-reforming processII. water–gas reactionIII. Haber processa. I onlyb. II onlyc. III onlyd. I and II onlye. II and III only
What was the argument used by Bartlett that led him to the first synthesis of a noble-gas compound?
How is sodium hypochlorite prepared? Give the balanced chemical equation.
What are some major commercial uses of chlorine?
A test tube contains a solution of one of the following salts: NaCl, NaBr, NaI. Describe a single test that can distinguish among these possibilities.
Give equations for the steps in the contact process for the manufacture of sulfuric acid from sulfur.
Give equations for preparing each of the following:a. H2Sb. SO2
Describe the Frasch process for mining sulfur.
Describe the structure of the rhombic sulfur molecule.
List three natural sources of sulfur or sulfur compounds.
Give an example of an acidic oxide and a basic oxide.
What reaction was used by Priestley in preparing pure oxygen?
What is the purpose of adding polyphosphates to a detergent?
Give chemical equations for the reaction of white phosphorus in an excess of air and for the reaction of the product with water.
List the different nitrogen oxides. What is the oxidation number of nitrogen in each?
Carbon monoxide is a poisonous gas. What is the mechanism of this poisoning?
What is meant by the term catenation? Give an example of a carbon compound that displays catenation.
The yellow paint pigment chrome yellow [lead(II) chromate] is produced by a precipitation reaction. Write an equation in which chrome yellow is produced from lead(II) nitrate.
What are some major uses of aluminum oxide?
Write the chemical equation of the thermite reaction, in which iron(III) oxide is reduced by aluminum.
Purified calcium carbonate is prepared by precipitation. Write the equation for the commercial process using carbon dioxide. You can also prepare calcium carbonate by precipitation using sodium
Calcium carbonate is used in some antacid preparations to neutralize the hydrochloric acid in the stomach. Write the equation for this neutralization.
Because magnesium reacts with oxygen, steam, and carbon dioxide, magnesium fires are extinguished only by smothering the fire with sand. Write balanced equations for the reactions of magnesium with
How is sodium hydroxide manufactured? What is another product in this process?
Ethanol, C2H5OH, reacts with sodium metal because the hydrogen atom attached to the oxygen atom is slightly acidic. Write a balanced equation for the reaction of sodium with ethanol to give the salt
Write the equation for the reaction of lithium carbonate with barium hydroxide.
What is the purpose of roasting lead(II) ore?
Give four characteristics of a metal.
What nuclide is formed when americium-241 undergoes alpha decay?
Write the nuclear equations for the following bombardment reactions.a.b. 45 21 Sc(n, a)K 42 19
Write the nuclear equations for the following bombardment reactions.a.b. Al(d, a)Mg 27 13
Write abbreviated notations for the following bombardment reactions.a.b. N + on C + H 14 1. 14,
Write the abbreviated notations for the following bombardment reactions.a.b. 24 26, 12 Mg + ?H iNa + He
Radon is a radioactive noble gas formed in soil containing radium. Radium-226 decays by emitting a single alpha particle to produce radon-222. Write the nuclear equation for this decay of radium-226.
Thorium is a naturally occurring radioactive element. Thorium-232 decays by emitting a single alpha particle to produce radium-228. Write the nuclear equation for this decay of thorium-232.
Write the nuclear equation for the decay of phosphorus- 32 to sulfur-32 by beta emission. A phosphorus-32 nucleus emits a beta particle and gives a sulfur-32 nucleus.
Rubidium-87, which forms about 28% of natural rubidium, is radioactive, decaying by the emission of a single beta particle to strontium-87. Write the nuclear equation for this decay of rubidium-87.
You have a pile of I-131 atoms with a half-life of 8 days. A portion of the solid I-131 is represented below. Can you predict how many half-lives will occur before the green I-131 atom undergoes
Neutron activation analysis is an analytical technique in which a sample of material is bombarded with neutrons from a fission reactor. When a 35.0-g aluminum can is irradiated, it has an initial
A radioactive isotope has a half-life of 56.6 days. What fraction of the isotope remains after 449 days?a. 3.2 × 106b. 1.00c. 0.92d. 4.1 × 103e. 0.83
The half-life for the decay of carbon-14 is 5730 years. Present-day carbon (in living matter) gives 15.3 disintegrations of 14C per minute per gram of total carbon. An archaeological sample
Polonium-216 decays to lead-212 by emission of an alpha particle. Which of the following is the nuclear equation for this radioactive decay? 212 a. 21PO Pb +e 84 82 b. 21PO - Pb + He c. 2Po + He- 212
Briefly describe how a nuclear fission reactor operates.
What is the age of a rock that contains equal numbers of 4019K and 4018Ar nuclei? The half-life of 4019K is 1.28 × 109y.
The half-life of cesium-137 is 30.2y. How long will it take for a sample of cesium-137 to decay to 1/8 of its original mass?
What are the isotopes that begin each of the naturally occurring radioactive decay series?
What are magic numbers? Give several examples of nuclei with magic numbers of protons.
Which of the following reactions occur spontaneously as written, with the production of a measurable electric current?a. I2 + NaBr → Br2 + 2NaIb. Li + NaCl → LiCl + Nac. Li+ + Na+ → NaLid. Ag +
The difference between a “heavy-duty” and a regular zinc–carbon battery is that the zinc can in the heavy-duty battery has thicker walls. What makes this battery heavy-duty in terms of output?
The composition of the hull of a submarine is mostly iron. Pieces of zinc, called “zincs,” are placed in contact with the hull throughout the inside of the submarine. Why is this done?
You are working at a plant that manufactures batteries. A client comes to you and asks for a 6.0-V battery that is made from silver and cadmium. Assuming that you are running the battery under
The voltaic cell is represented asWhich of the following statements is not true of this cell?a. The mass of the zinc electrode, Zn(s), decreases as the cell runs.b. The copper electrode is the
Electrolysis of an aqueous solution of sodium chloride produces chlorine, Cl2(g). The reaction that occurs at the anode isA constant electric current deposits 152 g Cl2 in 56.1 min from an aqueous
What half-reaction would be expected to occur at the cathode in the electrolysis of aqueous sodium fluoride?a. 2F(aq) → F2(g) + 2eb. 2H2O(l) → O2(g) + 4H+(aq) + 4ec. 2H2O(l) + 2e → H2(g) +
The following oxidation–reduction reaction occurs in acidic solution. When the equation is balanced using the smallest set of whole-number stoichiometric coefficients possible, what is the
The electrolysis of water is often done by passing a current through a dilute solution of sulfuric acid. What is the function of the sulfuric acid?
Describe a method for the preparation of sodium metal from sodium chloride.
Express the SI unit of energy as the product of two electrical units.
Define the faraday.
What is the SI unit of electrical potential?
Define cathode and anode.
Ethanol burns in air or oxygen according to the equationPredict the sign of ΔS° for this reaction. C,H;OH(l) + 30,(8) → 2CO,(g) + 3H,O(g)
The following equation shows how nitrogen dioxide reacts with water to produce nitric acid:Predict the sign of ΔS° for this reaction. 3NO2(8) + H2O(I) → 2HNO3(I) + NO(g)
Given the following information at 25°C, calculate ΔG° at 25°C for the reactiona. 956 kJb. 956 kJc. 346 kJd. 346 kJe. 1.03 × 103 kJ 2A(g) + B(g) 3C(g) Substance AH¡ (kJ/mol) S°(J/mol·K)
A reaction has a ΔG = 10.0 kJ and a ΔH = 20.0 kJ.If ΔS = 1.82 × 103 J/K, what was the temperature at which the reaction occurred?a. 6.04 Kb. 6.04 × 103 Kc. 5.49 × 103 Kd. 5.49 Ke.
You run a reaction that has a negative entropy change and is exothermic. Assuming that the entropy and enthalpy do not change with temperature, you could predict that as you increase the
Which of the following are true about the process of water making the transition from the liquid to the gaseous state at 110°C?a. ΔG > 0, ΔH < 0, and ΔS = 0b. ΔG < 0, ΔH > 0, and
What is the useful work obtained in the ideal situation in which a chemical reaction with free energy change ΔG is run so that it produces no entropy?
Define the free energy G. How is ΔG related to ΔH and ΔS?

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