A 0.500-g mixture of Cu2O and CuO contains 0.425 g Cu. What is the mass of CuO in the mixture?
You react nitrogen and hydrogen in a container to produce ammonia, NH3(g). The following figure depicts the contents of the container after the reaction is complete. a. Write a balanced chemical...
Calculate the mass in grams of the following. a. 0.15 mol Na b. 0.594 mol S c. 2.78 mol CH2Cl2 d. 38 mol (NH4)2S
A sample of an alloy of aluminum contains 0.0898 mol Al and 0.0381 mol Mg. What are the mass percentages of Al and Mg in the alloy?
Iron in the form of fine wire burns in oxygen to form iron(III) oxide. 4Fe(s) + 3O2(g) 2Fe2O3(s) How many moles of O2 are needed to produce 3.91 mol Fe2O3?
Methyl salicylate (oil of wintergreen) is prepared by heating salicylic acid, C7H6O3, with methanol, CH3OH. C7H6O3 + CH3OH C8H8O3 + H2O In an experiment, 1.50 g of salicylic acid is reacted with...
A stock solution of potassium dichromate, K2Cr2O7, is made by dissolving 89.3 g of the compound in 1.00 L of solution. How many milliliters of this solution are required to prepare 1.00 L of 0.100 M...
A solution contains 6.00% (by mass) NaBr (sodium bromide). The density of the solution is 1.046 g/cm3. What is the molarity of NaBr?
You have a sample of a rat poison whose active ingredient is thallium(I) sulfate. You analyze this sample for the mass percentage of active ingredient by adding potassium iodide to precipitate yellow...
A transition metal X forms an oxide of formula X2O3. It is found that only 50% of X atoms in this compound are in the +3 oxidation state. The only other stable oxidation states of X are +2 and +5....
A sample of natural gas is 85.2% methane, CH4, and 14.8% ethane, C2H6, by mass. What is density of this mixture at 18oC and 771 mmHg?
A mixture contained zinc sulfide, ZnS, and lead sulfide, PbS. A sample of the mixture weighing 6.12 g was reacted with an excess of hydrochloric acid. The reactions are ZnS(s) + 2HCl(aq) ZnCl2(aq) +...
A sample of nitrogen gas at 18oC and 760 mmHg has a volume of 3.92 mL. What is the volume at 0oC and 1 atm of pressure?
A piece of iron was heated to 95.4oC and dropped into a constant-pressure calorimeter containing 284 g of water at 32.2oC. The final temperature of the water and iron was 51.9oC. Assuming that the...
How much heat is released when a mixture containing 10.0 g NH3 and 20.0 g O2 reacts by the following equation? 4NH3(g) + 5O2(g) 4NO(g) + 6H2O(g); H = 906 kJ
Consider the Haber process: N2(g) + 3H2(g) 2NH3(g); H = 91.8 kJ The density of ammonia at 25oC and 1.00 atm is 0.696 g/L. The density of nitrogen, N2, is 1.145 g/L, and the molar heat capacity is...
A rebreathing gas mask contains potassium superoxide, KO2, which reacts with moisture in the breath to give oxygen. 4KO2(s) + 2H2O(l) 4KOH(s) + 3O2(g) Estimate the grams of potassium superoxide...
A sample of benzene, C6H6, weighing 3.51 g was burned in an excess of oxygen in a bomb calorimeter. The temperature of the calorimeter rose from 25.00oC to 37.18oC. If the heat capacity of the...
An ionic compound has the following composition (by mass): Mg, 10.9%; Cl, 31.8%; O, 57.3%. What are the formula and name of the compound? Write the Lewis formulas for the ions.
(a) Nitrogen trifluoride, NF3, is a relatively unreactive, colorless gas. How would you describe the bonding in the NF3 molecule in terms of valence bond theory? Use hybrid orbitals. (b) Silicon...
For the hydrogen halides and the noble gases, we have the following boiling points: Halogen Family, C Noble Gases, C HF, 19 ....... Ne, 246 HCl, 115 Ar, 186 HBr, 67 .. Kr, 152 HI, 35 ...... Xe, 108...
Account for the following observations: a. Both diamond and silicon carbide are very hard, whereas graphite is both soft and slippery. b. Carbon dioxide is a gas, whereas silicon dioxide is a...
An aqueous solution is 2.00 M urea. The density of the solution is 1.029 g/mL. What is the molal concentration of urea in the solution?
A liter of water at 25C dissolves 0.0404 g O2 when the partial pressure of the oxygen is 1.00 atm. What is the solubility of oxygen from air, in which the partial pressure of O2 is 159 mmHg?
Toluene, C6H5CH3, is a liquid compound similar to benzene, C6H6. It is the starting material for other substances, including trinitrotoluene (TNT). Find the molality of toluene in a solution that...
A solution is 0.120 m methanol dissolved in ethanol. Calculate the mole fractions of methanol, CH3OH, and ethanol, C2H5OH, in the solution.
Analysis of a compound gave 39.50% C, 2.21% H, and 58.30% Cl. When 0.855 g of this solid was dissolved in 7.50 g of naphthalene, the solution had a freezing point of 78.0C. The pure solvent freezes...
A salt solution has an osmotic pressure of 17 atmospheres at 22C. What is the freezing point of this solution? What assumptions must be made to solve this problem?
A solution is made up by dissolving 15.0 g MgSO47H2O in 100.0 g of water. What is the molality of MgSO4 in this solution?
Ten grams of the hypothetical ionic compounds XZ and YZ are each placed in a separate 2.0-L beaker of water. XZ completely dissolves, whereas YZ is insoluble. The energy of hydration of the Y+ ion is...
An automobile antifreeze solution contains 2.50 kg of ethylene glycol, CH2OHCH2OH, and 2.00 kg of water. Find the mole fraction of ethylene glycol in this solution. What is the mole fraction of water?
A solution of vinegar is 0.763 M acetic acid, HC2H3O2. The density of the vinegar is 1.004 g/mL. What is the molal concentration of acetic acid?
A solution was prepared by dissolving 0.834 g of sulfur, S8, in 100.0 g of acetic acid, HC2H3O2. Calculate the freezing point and boiling point of the solution.
Arginine vasopressin is a pituitary hormone. It helps regulate the amount of water in the blood by reducing the flow of urine from the kidneys. An aqueous solution containing 21.6 mg of vasopressin...
A natural gas mixture consists of 90.0 mole percent CH4 (methane) and 10.0 mole percent C2H6 (ethane). Suppose water is saturated with the gas mixture at 20C and 1.00 atm total pressure, and the gas...
An aqueous solution is 8.50% ammonium chloride, NH4Cl, by mass. The density of the solution is 1.024 g/mL. What are the molality, mole fraction, and molarity of NH4Cl in the solution?
An aqueous solution is 27.0% lithium chloride, LiCl, by mass. The density of the solution is 1.127 g/mL. What are the molality, mole fraction, and molarity of LiCl in the solution?
At 330oC, the rate constant for the decomposition of NO2 is 0.775 L/(mols). If the reaction is second order, what is the concentration of NO2 after 2.5 102 seconds if the starting concentration was...
A second-order reaction has a rate constant of 8.7 104/(Ms) at 30oC. At 40oC, the rate constant is 1.8 103/(Ms). What are the activation energy and frequency factor for this reaction? Predict the...
Acetone reacts with iodine in acidic aqueous solution to give monoiodoacetone. A possible mechanism for this reaction is Write the rate law that you derive from this mechanism.
Ammonium nitrite, NH4NO2, decomposes in solution, as shown here. NH4NO2(aq) N2(g) + 2H2O(l ) The concentration of NH4+ ion at the beginning of an experiment was 0.500 M. After 3.00 hours, it was...
Sulfuryl chloride, SO2Cl2, decomposes when heated. SO2Cl2(g) SO2(g) + Cl2(g) In an experiment, the initial concentration of SO2Cl2 was 0.0248 mol/L. If the rate constant is 2.2 105/s, what is the...
A reaction of the form aA Products is second-order with a rate constant of 0.225 L/(mols). If the initial concentration of A is 0.293 mol/L, what is the molar concentration of A after 35.4 s?
A reaction of the form aA Products is second order with a rate constant of 0.169 L/(mols). If the initial concentration of A is 0.159 mol/L, how many seconds would it take for the concentration of A...
A reaction of the form aA Products is second order with a rate constant of 0.413 L/(mols). What is the half-life, in seconds, of the reaction if the initial concentration of A is 5.25 103 mol/L?
A reaction of the form aA Products is second order with a half-life of 425 s. What is the rate constant of the reaction if the initial concentration of A is 5.99 103 mol/L?
Calculate the composition of the gaseous mixture obtained when 1.25 mol of carbon dioxide is exposed to hot carbon at 800oC in a 1.25-L vessel. The equilibrium constant Kc at 800oC is 14.0 for the...
An equilibrium mixture of SO3, SO2, and O2 at 727oC is 0.0160 M SO3, 0.0056 M SO2, and 0.0021 M O2. What is the value of Kc for the following reaction? SO3(g)
An equilibrium mixture of dinitrogen tetroxide, N2O4, and nitrogen dioxide, NO2, is 65.8% NO2 by mass at 1.00 atm pressure and 25oC. Calculate Kc at 25oC for the reaction N2O4(g) 2NO2(g)
A vessel originally contained 0.200 mol iodine monobromide (IBr), 0.0010 mol I2, and 0.0010 mol Br2. The equilibrium constant Kc for the reaction is 1.2 102 at 150oC. What is the direction (forward...
A saturated solution of calcium hydroxide has a hydroxide-ion concentration of 0.025 M. What is the pH of the solution?
What is meant by the conjugate acid of a base?
A solution made up of 1.0 M NH3 and 0.50 M (NH4)2SO4 has a pH of 9.26. a. Write the net ionic equation that represents the reaction of this solution with a strong acid. b. Write the net ionic...
A solution of acetic acid, HC2H3O2, on a laboratory shelf was of undetermined concentration. If the pH of the solution was found to be 2.68, what was the concentration of the acetic acid?
What is the concentration of hydroxide ion in a 0.060 M aqueous solution of methylamine, CH3NH2? What is the pH?
Adenosine triphosphate (ATP) is often referred to as a biological energy source. What does this mean? Explain how ATP is used in biological organisms to produce proteins from amino acids.
Radium-226 decays by alpha emission to radon-222, a noble gas. What volume of pure radon-222 at 23C and 785 mmHg could be obtained from 543.0 mg of radium bromide, RaBr2, in a period of 37.5 y? The...
A uranium-235 nucleus decays by a series of alpha and beta emissions until it reaches lead 207. How many alpha emissions and how many beta emissions occur in this series of decays?
Use thermodynamic data to calculate the standard enthalpy change for the decomposition of water vapor to atoms in the gas phase. From this, obtain a value for the OH bond energy. Similarly, obtain...
Write the balanced equation for the reaction of sulfurous acid with dichromate ion.
Name the following compounds by IUPAC rules: a. b. H-C CH,CH-CH
(a) What is meant by the term standard conditions with reference to enthalpy changes? (b) What is meant by the term enthalpy of formation? (c) What is meant by the term standard enthalpy of formation?
Given the data use Hess's law to calculate ÎH for the reaction N2(g) + O2(g)- 2 NO(g) 2 NO(g) + O2(g)-2 NO2(g) AFI + 180.7 kJ --I 13.1 kJ --163.2 kl 2N2O(g)--> 2N2(g) + O2(g) N20(g) + NO2(g)3...
Using values from Appendix C, calculate the value of H for each of the following reactions: (a) CaO(s) + 2 HCl(g) CaCl2(s) + H2O(g) (b) 4 FeO(s) + O2(g) 2 Fe2O3(s) (c) 2 CuO(s) + NO(g) Cu2O(s) +...
(a) What is meant by the term fuel value? (b) Which is a greater source of energy as food, 5 g of fat or 9 g of carbohydrate? (c) The metabolism of glucose produces CO2(g) and H2O(l). How does the...
NaCl and KF have the same crystal structure. The only difference between the two is the distance that separates cations and anions. (a) The lattice energies of NaCl and KF are given in Table 8.2....
(a) Use bond enthalpies to estimate the enthalpy change for the reaction of hydrogen with ethylene: H2 (g) + C2H4 (g) C2H6 (g) (b) Calculate the standard enthalpy change for this reaction, using...
Assume that an exhaled breath of air consists of 74.8% N2, 15.3% O2, 3.7% CO2 and 6.2% water vapor. (a) If the total pressure of the gases is 0.985 atm, calculate the partial pressure of each...
Which of the noble gases other than radon would you expect to depart most readily from ideal behavior? Use the density data in Table 7.8 to show evidence in support of your answer. TABLE 7.8Some...
Ammonia and hydrogen chloride react to form solid ammonium chloride: NH3 (g) + HCl (g) NH4CL (s) Two 2.00-L flasks at 25oC are connected by a valve, as shown in the drawing on the next page. One...
Complete the following table for an ideal gas: 0.500 mol ?K 2.00 atm 1.00L 0.300 atm 0.250 L 650 to ?L ? atm 27C 0.333 mo 350 K 585 mL 0.250 mo 295 K mol
A mixture containing 0.765 mol He (g), 0.330 mol Ne (g) and 0.110 mol Ar (g) is confined in a 10.00-L vessel at 25oC. (a) Calculate the partial pressure of each of the gases in the mixture. (b)...
(a) Place the following gases in order of increasing average molecular speed at 300 K: CO, SF6, H2S, Cl2, HBr. (b) Calculate and compare the rms speeds of CO and Cl2 molecules at 300 K. (c) Calculate...
Aluminum metal crystallizes in a cubic close-packed structure [face-centered cubic cell, Figure 12.14(a)]. (a) How many aluminum atoms are in a unit cell? (b) What is the coordination number of each...
(a) Explain why carbonated beverages must be stored in sealed containers. (b) Once the beverage has been opened, why does it maintain more carbonation when refrigerated than at room temperature?
A sulfuric acid solution containing 571.6 g of H2SO4 per liter of solution has a density of 1.329 g/cm3. Calculate (a) The mass percentage, (b) The mole fraction, (c) The molality, (d) The molarity...
Lauryl alcohol is obtained from coconut oil and is used to make detergents. A solution of 5.00 g of lauryl alcohol in 0.100 kg of benzene freezes at 4.1 oC. What is the approximate molar mass of...
Acetonitrile (CH3CN) is a polar organic solvent that dissolves a wide range of solutes, including many salts. The density of a 1.80 M LiBr solution in acetonitrile is 0.826 g/cm3. Calculate the...
A mixture of 0.2000 mol of CO2, 0.1000 mol of H2, and 0.1600 mol of H2O is placed in a 2.000-L vessel. The following equilibrium is established at 500 K: (a) Calculate the initial partial pressures...
Write a condensed structural formula for the following compound.
Write each of the following condensed structural formulas as a bond-line formula: (a) (CH3)2CHCH2CH3 (b) (CH3)2CHCH2CH2OH (c) (CH3)2C==CHCH2CH3 (d) CH3CH2CH2CH2CH3 (e) CH3CH2CH(OH)CH2CH3 (f) CH2...
(a) Write two resonance structures for the formate ion HCO2-.(The hydrogen and oxygen atoms are bonded to the carbon.) (b) Explain what these structures predict for the carbon-oxygen bond lengths of...
Use VSEPR theory to predict the geometry of each of the following molecules and ions: (a) H4 (b) BeF2 (c) (d) H2S (e) BH3 (f) CF4 (g) SiF4 (h)
Write the resonance structure that would result from moving the electrons as the curved arrows indicate. Be sure to include formal charges if needed. (a) (b) (c) (d) 079 HIN:
Open computer molecular models for dimethyl ether, dimethylacetylene, and cis-1,2- ichloro-1,2-difluoroethene from the 3D Molecular Models section of the book's website. By interpreting the computer...
Write bond-line structural formulas for (a) Two constitutionally isomeric primary alkyl bromides with the formula C4H9Br, (b) A secondary alkyl bromide, and (c) A tertiary alkyl bromide with the same...
Hydrogen fluoride has a dipole moment of 1.83 D; its boiling point is 19.34oC. Ethyl fluoride (CH3CH2F) has an almost identical dipole moment and has a larger molecular weight, yet its boiling point...
Tetrachloroethene (CCl2==CCl2) does not have a dipole moment. Explain this fact on the basis of the shape of CCl2==CCl2.
In infrared spectra, the carbonyl group is usually indicated by a single strong and sharp absorption. However, in the case of carboxylic acid anhydrides, two peaks are observed even though the two...
Write structural formulas for four compounds with the formula C3H6O and classify each according to its functional group. Predict IR absorption frequencies for the functional groups you have drawn.
The compounds in each part below have the same (or similar) molecular weights. Which compound in each part would you expect to have the higher boiling point? Explain your answers. (a) (b) (c) OH or...
There are four amides with the formula C3H7NO. (a) Write their structures. (b) One of these amides has a melting and a boiling point that are substantially lower than those of the other three. Which...
Cyclic compounds of the general type shown here are called lactones. What functional group does a lactone contain?
Examine the diagram showing an a-helical protein structure in Section 2.13E. Between what specific atoms and of what functional groups are the hydrogen bonds formed that give the molecule its helical...
Using a three-dimensional formula, show the direction of the dipole moment of CH3OH. Write (+ and (- signs next to the appropriate atoms.
Classify the following amines as primary, secondary, or tertiary: (a) (b) (c) (d) (e) (f) H IN NH2 HN
Write structural formulas for each of the following: (a) Three ethers with the formula C4H10O. (b) Three primary alcohols with the formula C4H8O. (c) A secondary alcohol with the formula C3H6O. (d) A...
Predict the key IR absorption bands whose presence would allow each compound in pairs (a), (c), (d), (e), (g), and (i) from Problem 2.46 to be distinguished from each other. In problems 2.46 (a) (c)...
Indicate the direction of the important bond moments in each of the following compounds (neglect C-H bonds). You should also give the direction of the net dipole moment for the molecule. If there is...
Write structures for all compounds with molecular formula C4H6O that would not be expected to exhibit infrared absorption in the 3200-3550-cm-1 and 1620-1780-cm-1 regions.