Questions and Answers of General Chemistry

Suppose that an aqueous solution is in equilibrium with solid calcium sulfate and solid barium sulfate. What are the concentrations of calcium ion and barium ion in the solution?
The solubility of silver iodate, AgIO3, in water is 0.051 g/L. Calculate Ksp.
Calculate the pH of a 0.10 M aqueous solution of zinc chloride, ZnCl2. The acid ionization of hydrated zinc ion is Zn(H2O)62+(aq) + H2O(l) ⇌ Zn(H2O)5OH+(aq) + H3O+(aq) and Ka is 2.5 × 10-10.
A 18.0-g sample of rubber (poly-cis-isoprene) reacts with bromine, Br2, to produce the polymer in which bromine adds to each of the double bonds. Estimate the quantity of heat that evolves in this
Consider the condensation of the diamine H2N(CH2)n NH2 with sebacic acid, (HOOC)(CH2)8(COOH), to obtain the polyamide. The polyamide has the following composition: 66.1% C, 10.3% H, 11.0% N, and
If a sample of DNA isolated from a microorganism culture were analyzed and found to contain 3.5 mol of cytosine nucleotides and 4.5 mol of adenosine nucleotides, what would be the amounts of guanine
Find the positive solution (or solutions) to the following equation:1.80x2 + 0.850x − 9.50 = 0
Evaluate a. ln 9.93; b. e1.10.
Evaluate a. Antilog 5.728; b. Antilog (−5.728).
Find the values of a. log 0.00582; b. log 689.
Obtain the values of the following, and express them in scientific notation:a. (3.56 × 103)4b. 3√4.81 × 102
Perform the following operations, expressing the answers in scientific notation:a. (5.4 × 10−7) × (1.8 × 108)b. 5.4 × 10-7/6.0 × 10-5
Add the following, and express the sum in scientific notation:(3.142 × 10−4) + (2.8 × 10−6)
Convert the following numbers in scientific notation to usual form:a. 7.025 × 103b. 8.97 × 10−4
Express the following numbers in scientific notation:a. 4.38b. 4380c. 0.000483
Complete and balance the reaction for each of the following undergoing a combustion reaction.a. 2-methylpentaneb. 2,2-dimethylpropanec. 3-methyl-3-hexened. 3-ethyl-3-propanole. ethylbenzene
Indicate the molecular geometry around each carbon atom in the compound H;CCH=CHCH,CCH,COOH
Draw the cis and trans isomers of the compound 3-methyl-3-hexene.
Amino acids are important biological molecules. Using the name amino acid as a guide, write the name and structure of the functional groups common to all amino acids.
Write structural formulas for a. 1,2,4-trimethylbenzeneb. o-diethylbenzene.
Write structural formulas for a. 1,1,1-triphenylethane; b. o-ethylmethylbenzene
Write an equation for a possible substitution reaction of butane, C4H10, with Cl2.
Write an equation for a possible substitution reaction of ethane, C2H6, with Br2.
Draw structural formulas of an alkane, a cycloalkane, an alkene, and an aromatic hydrocarbon, each with eight carbon atoms.
For gasoline to function properly in an engine, it should not begin to burn before it is ignited by the spark plug. If it does, it makes the noise we think of as engine “knock.” The octane-number
Give the molecular formula of an alkane with 25 carbon atoms.
Consult Figure 22.27, which depicts the absorption versus wavelength curve for the [Ti(H2O)6]3+ ion.a. What is the absorbance maximum (wavelength) of this ion?b. If you were to make the [Ti(CN)6]3−
Consider the tetracarbonyldibromoiron(II) ion.a. Write the chemical formula of the compound.b. How many geometric isomers are possible for this compound?c. Does the compound have optical isomers?
Is it possible to have a paramagnetic d 4-tetrahedral complex ion? Explain.
What is the name of K2[MoOCl4]?
What is the value of ∆ (in kJ/mol) when λ = 454 nm, corresponding to an electron jump between d-orbital levels in a complex with a d1 configuration?
The [CoF6]3− ion has a maximum absorption at 700 nm. What color do you expect for this ion?
a. Use crystal field theory to describe a high-spin octahedral complex of Cr2+. b. Do the same for a low-spin complex.
Silver(I) ion in basic solution is reduced by formaldehyde, HCHO, to Ag metal. Formaldehyde is oxidized to formate ion, HCOO−. Write the balanced equation for this reaction.
According to the building-up principle, what is the electron configuration of the ground state of the yttrium atom (atomic number 39)?
A complex has the composition Co(NH3)4(H2O)BrCl2. Conductance measurements show that there are three ions per formula unit, and precipitation of AgCl with silver nitrate shows that there are two
Write structural formulas for each of the following:a. Potassium hexacyanoferrate(II), b. Tetraamminedichlorocobalt(III) chloride, c. Tetrachloroplatinate(II) ion.
Another complex studied by Werner had a composition corresponding to the formula PtCl4∙2KCl. From electrical-conductance measurements, he determined that each formula unit contained three ions. He
Give the IUPAC names of a. [Co(NH3)5Cl]Cl2;b. K2[Co(H2O)(CN)5]; c. [Fe(H2O)5(OH)]2+.
According to an analysis, a sample of phosphate rock contains 73.7% Ca3(PO4)2, by mass. How many grams of calcium dihydrogen phosphate, Ca(H2PO4)2, can be obtained from 10.1 g of phosphate rock from
Ammonia reacts with oxygen in the presence of a platinum catalyst to give nitric oxide, NO. How many grams of oxygen are required in this reaction to give 3.10 g NO?
Silicon is purified by first converting it to silicon tetrachloride, which is then distilled. How many kilograms of silicon are required to prepare 5.70 kg of SiCl4?
How much heat will be evolved when 22.7 grams of the binary covalent hydride HF is produced via the following reaction?F2(g) + H2(g) → 2HF(g) ΔH = -545 kJ
You have a 0.28 M solution of magnesium ion. How many grams of calcium hydroxide must be added to 52.5 mL of the solution to precipitate all of the magnesium ion?
You have a 0.19 M solution of calcium hydrogen carbonate. How many grams of calcium hydroxide must be added to 25.0 mL of the solution to precipitate all of the calcium?
How many energy levels are there in the 3p band of a single crystal of magnesium with a mass of 1.10 mg?
How many energy levels are there in the valence band of a single crystal of sodium with a mass of 2.50 mg?
How many kilograms of manganese can be produced from 2.50 kg of aluminum, Al, when you reduce manganese(IV) oxide?
Give the equation for the reaction used by the Swedish chemist Scheele to prepare chlorine.
Why do we need such low temperatures to liquefy gases such as nitrogen, oxygen, and helium?
Considering the fact that N2 makes up about 80% of the atmosphere, why don’t animals use the abundant N2 instead of O2 for biological reactions?
Radium-226 decays by alpha emission to radon-222, a noble gas. What volume of pure radon-222 at 23°C and 755 mmHg could be obtained from 543.0 mg of radium bromide, RaBr2, in a period of 37.5 y? The
A sample of sodium thiosulfate, Na2S2O3, weighing 43.6 mg contains radioactive sulfur-35 (with mass 35.0 amu). If 22.3% of the sulfur atoms in the compound is sulfur-35 (the remainder is naturally
A sample of sodium phosphate, Na3PO4, weighing 32.4 mg contains radioactive phosphorus-32 (with mass 32.0 amu). If 22.3% of the phosphorus atoms in the compound is phosphorus-32 (the remainder is
Sodium has only one naturally occurring isotope that is not radioactive.a. What is the mass defect of sodium?b. What is the nuclear binding energy (MeV) of a sodium nucleon?
Californium-251 was synthesized at the University of California in 1950. What type of decay would you predict for Cf-251? Write the balanced nuclear reaction for this decay.
Plutonium-239 is a fissionable material used in the construction of nuclear weapons and has a half-life of 24,100 years. Approximately 2 × 104 kg of plutonium is produced per year. How long would it
Radon-222 gas can be found seeping from granite that contains uranium-238. Radon-222 is a nuclide in the radioactive decay series of uranium-238. Radon is an element with a half-life of 3.82 days.a.
Samarium-153 is used in a drug to treat bone disorders. Sm has an activity of 8.6 Ci per mg.a. What is the rate constant of Sm-153?b. What is the half-life of Sm-153.c. In the United States,
Carbon from a cypress beam obtained from the tomb of Sneferu, a king of ancient Egypt, gave 8.8 disintegrations of 14C per minute per gram of carbon. How old is the cypress beam? Carbon from living
A sample of silver-112 gives a reading of 875 counts per hour on a radiation counter. After 0.25 h, the sample gives a reading of 400 counts per hour. What is the half-life (in hours) of silver-112?
A sample of iron-59 initially registers 165 counts per second on a radiation counter. After 11.0 d, the sample registers 139 counts per second. What is the half-life (in days) of iron-59?
If 24.0% of a sample of radioisotope decays in 8.73 s, what is the half-life of this isotope (in seconds)?
A solution of sodium iodide containing iodine-131 was given to a patient to test for malfunctioning of the thyroid gland. What fraction of the iodine-131 nuclei would remain undecayed after 5.0 d? If
A sample of sodium thiosulfate, Na2S2O3, contains sulfur-35. Determine the mass of 35S in the sample from the decay rate, which was determined to be 7.3 × 1011 disintegrations per second. The
A sample of a phosphorus compound contains phosphorus-32. This sample of radioactive isotope is decaying at the rate of 6.3 × 1012 disintegrations per second. How many grams of 32P are in the
Gold-198 has a half-life of 2.69 d. What is the activity (in curies) of a 0.92-mg sample?
A 4.00 × 10−2 -mol sample of a radioisotope has an activity of 56.5 Ci. What is the decay constant of the isotope (in /s)?
Why do you think that carbon-14 dating is limited to less than 50,000 years?
Two identical pieces of the same unknown metal are placed into 1.0 M solutions of LiNO3(aq) and Fe(NO3)2(aq). No reaction is observed in the LiNO3(aq); however, the metal appears to dissolve in the
A cell is constructed from some unknown elements designated as X and Y. Under standard conditions, a cell is created: X(s)| X3+(aq)||Y+(aq)| Y(s). The maximum freeenergy change for the reaction is
A 1.0-L sample of 1.0 M HCl solution has a 10.0 A current applied for 45 minutes. What is the pH of the solution after the electricity has been turned off?
A beaker is found to contain I−(aq), Cu2+(aq), and Mg2+(aq) ions with Ag(s).a. Would there be any spontaneous electrochemical reactions occurring in the mixture?b. A strip of aluminum metal is
Why are lithium-ion batteries especially desirable for portable devices like cell phones?
What is the anode material (during discharge) for a common lithium-ion battery? What is the cathode material for this battery?
An aqueous solution of an unknown salt of gold is electrolyzed by a current of 2.75 amps for 3.39 hours. The electroplating is carried out with an efficiency of 93.0%, resulting in a deposit of
A constant current of 1.40 amp is passed through an electrolytic cell containing a 0.100 M solution of AgNO3 and a silver anode and a platinum cathode until 2.48 g of silver is deposited.a. How long
How many faradays are required for each of the following processes? How many coulombs are required?a. Reduction of 2.0 mol Fe3+ to Fe2+b. Reduction of 2.0 mol Fe3+ to Fec. Oxidation of 2.5 g Sn2+ to
How many grams of cadmium are deposited from an aqueous solution of cadmium sulfate, CdSO4, when an electric current of 1.75 A flows through the solution for 325 min?
When molten lithium chloride, LiCl, is electrolyzed, lithium metal is liberated at the cathode. How many grams of lithium are liberated when 2.00 × 103 C of charge passes through the cell?
Describe what you expect to happen when the following solutions are electrolyzed: a. Aqueous Na2SO4; b. Aqueous KBr. That is, what are the electrode reactions? What is the overall reaction?
Consider the reducing agents Sn2+(aq), Cl2(g), and I−(aq). Which is strongest? Which is weakest?
What is ∆G° at 25°C for the reactionSn2+(aq) + 2Hg2+(aq) → Sn4+(aq) + Hg22+(aq)For data, see Table 19.1.
Define the faraday.
Keeping in mind that seawater contains a number of ions, explain why seawater corrodes iron much faster than freshwater.
Write the notation for a cell in which the electrode reactions are2H+(aq) + 2e- → H2(g)Zn(s) → Zn2+(aq) + 2e-
Define cathode and anode.
If you were to construct a wet cell and decided to replace the salt bridge with a piece of copper wire, would the cell produce a sustainable current? Explain your answer
Hydrogen bromide dissociates into its gaseous elements, H2 and Br2, at elevated temperatures. Calculate the percent dissociation at 317°C and 1.00 atm. What would be the percent dissociation at
Consider the reaction of methane, CH4(g), with oxygen, O2(g), to produce carbon dioxide, CO2(g), and water, H2O(l), taking place in a closed container. What is the entropy change at 25°C due to the
A truck weighing 1600 kg uses natural gas as fuel. Natural gas is mainly methane, CH4, and though it is normally a gas, it is stored in a tank as compressed liquid. Assume that the fuel is methane
Ammonia, NH3, is produced from its elements in the industrial Haber process. Calculate ∆H°, ∆G°, and ∆S° at 25°C. See Appendix C for data. The industrial process is run at temperatures
Tetrachloromethane (carbon tetrachloride), CCl4, has a normal boiling point of 76.7°C and an enthalpy of vaporization, ∆Hvap°, of 29.82 kJ/mol. Estimate the entropy of vaporization, ∆Svap°.
According to a source, lithium peroxide (Li2O2) decomposes to lithium oxide (Li2O) and oxygen gas at about 195°C. If the standard enthalpy change for this decomposition is 33.9 kJ/mol, what would
Sodium acetate crystallizes from a supersaturated solution (see Figure 12.4). What can you say about the sign of ∆G°? What would you expect for the sign of ∆S°? What about the sign of ∆H°?
A quantity of strong acid is added to pure water to give a solution that is 0.100 M H+. Calculate Q for the following reaction just as the H+ ion is added and before equilibrium is
Chloroform, CHCl3, is a solvent and has been used as an anesthetic. The heat of vaporization of chloroform at its boiling point (61.2°C) is 29.6 kJ/mol. What is the entropy change when 5.10 mol
Consider the reaction of nitrogen, N2, and oxygen, O2, to form nitrogen monoxide, NO:N2(g) + O2(g) → 2NO(g)From the standard free energy of formation of NO, what can you say about this reaction?
You have a sample of 1.0 mg of solid iodine at room temperature. Later, you notice that the iodine has sublimed (passed into the vapor state). What can you say about the change of entropy of the
The text describes zinc hydroxide as an amphoteric hydroxide, so Zn(OH)2 is soluble in basic solution. What is the molar solubility of Zn(OH)2 in 1.00 M NaOH? What is the pH of the equilibrium

Showing 1 - 100 of 1219