Ethylene glycol (HOCH2CH2OH), the major substance in antifreeze, has a normal boiling point of 198 °C. By comparison, ethyl alcohol (CH3CH2OH) boils at 78 °C at atmospheric pressure. Ethylene glycol dimethyl ether (CH3OCH2CH2OCH3) has a normal boiling point of 83 °C, and ethyl me...
23 Aug 2021a) Draw the best Lewis structure(s) for the nitrite ion, NO2b) With what allotrope of oxygen is it isoelectronic? (c) What would you predict for the lengths of the bonds in NO2 relative to N – O single bonds and double bonds?
23 Aug 2021Arrange the following 0.10 M solutions in order of increasing acidity (decreasing pH): (i) NH4NO3, (ii) NaNO3, (iii) CH3COONH4, (iv) NaF, (v) CH3COONa.
23 Aug 2021Indicate 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 of a postage stamp, (e) the number of milliliters in a cubic meter of water, (...
23 Aug 2021The 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?
23 Aug 2021Tooth enamel is composed of hydroxyapatite, whose simplest formula is Ca5(PO43OH, and whose corresponding Ksp = 6.8 × 10-27. As discussed in the “Chemistry and Life” box on page 755, fluoride in fluorinated water or in toothpaste reacts with hydroxyapatite to form fluoroapatite, ...
23 Aug 2021Ammonia (NH3) boils at –33 °C; at this temperature it has a density of 0.81 g/cm3. The enthalpy of formation of NH3g) is –46.2 kJ/mol, and the enthalpy of vaporization of NH3l) is 23.2 kJ/mol. Calculate the enthalpy change when 1 L of liquid NH3 is burned in air to give N2g) and ...
23 Aug 2021Calculate the cell potential for the galvanic cell in which the given reaction occurs at , given that and . Standard reduction potentials of and are and , respectively. The overall equation is:
23 Aug 2021The concentration of Ca2 in a particular water supply is 5.7 × 10-3M. The concentration of bicarbonate ion, HCO3, in the same water is 1.7 × 10-3M. What masses of Ca(OH)2 and Na2CO3 must be added to 5.0 × 107 L of this water to reduce the level of Ca2 to 20% of its original level...
23 Aug 2021Seawater contains 3.4 g of salts for every liter of solution. Assuming that the solute consists entirely of NaCl (in fact, over 90% of the salt is indeed NaCl), calculate the osmotic pressure of seawater at 20 °C.
23 Aug 2021Gold is alloyed (mixed) with other metals to increase its hardness in making jewelry. (a) Consider a piece of gold jewelry that weighs 9.85 g and has a volume of 0.675 cm3. The jewelry contains only gold and silver, which have densities of 19.3 and 10.5 g/cm3, respectively. If th...
23 Aug 2021To calibrate your calorimeter cup, you first put 59 mL of cold water in the cup, and measure its temperature to be 18.7 °C. You then pour 51 mL of hot water, temperature = 52.1 °C, into the cup and measure the temperature every thirty seconds over a 10 minute period. You extrapol...
23 Aug 2021a) What is the relationship between the wavelength and the frequency of radiant energy? (b) Ozone in the upper atmosphere absorbs energy in the 210–230-nm range of the spectrum. In what region of the electromagnetic spectrum does this radiation occur?
23 Aug 2021Pure acetic acid, known as glacial acetic acid, is a liquid with a density of 1.049 g/mL at 25 °C. Calculate the molarity of a solution of acetic acid made by dissolving 20.00 mL of glacial acetic acid at 25 °C in enough water to make 250.0 mL of solution.
23 Aug 2021With reference to the Chemistry Put to Work box on explosives, (a) use bond enthalpies to estimate the enthalpy change for the explosion of 1.00 g of nitroglycerin. (b) Write a balanced equation for the decomposition of TNT. Assume that, upon explosion, TNT decomposes into N2g), ...
23 Aug 2021The hydroxyl radical, OH, is formed at low altitudes via the reaction of excited oxygen atoms with water:O*(g) H2O(g 2 OH(g(a) Write the Lewis structure for the hydroxyl radical. (Hint: It has one unpaired electron.) Once produced, the hydroxyl radical is very reactive. Explain ...
23 Aug 2021Although the electron affinity of bromine is a negative quantity, it is positive for Kr. Use the electron configurations of the two elements to explain the difference.
23 Aug 2021The half-life for the process 238U 206Pb is 4.5 × 109 yr. A mineral sample contains 75.0 mg of 238U and 18.0 mg of 206Pb. What is the age of the mineral?
23 Aug 2021When it became too hot to stay outside during a summer birthday party, the party was moved inside to an air‑conditioned porch. If a latex balloon has a volume of 7.50 L at 34 °C, what would be the volume of this balloon at 21 °C? Assume that the pressure does not change.
23 Aug 2021Prostaglandins are a class of eicosanoids, fatty acid derivatives with a variety of extremely potent actions on vertebrate tissues. They are responsible for producing fever and inflammation and its associated pain. Prostaglandins are derived from the 20-carbon fatty acid arachido...
23 Aug 2021Title of Appendix B lists the vapor pressure of water at various external pressures. (a) Plot the data in Title of Appendix B, vapor pressure (torr) versus temperature (°C). From your plot, estimate the vapor pressure of water at body temperature, 37 °C. (b) Explain the signifi...
23 Aug 2021a) What is a hydrocarbon? (b) Pentane is the alkane with a chain of five carbon atoms. Write a structural formula for this compound and determine its molecular and empirical formulas.
23 Aug 2021You are presented with a white solid and told that due to careless labeling it is not clear if the substance is barium chloride, lead chloride, or zinc chloride. When you transfer the solid to a beaker and add water, the solid dissolves to give a clear solution. Next a Na2SO4aq) ...
23 Aug 2021The standard enthalpies of formation of ClO and ClO2 are 101 and 102 kJ/mol, respectively. Using these data and the thermodynamic data in Appendix C, calculate the overall enthalpy change for each step in the following catalytic cycle:ClO(g) O3g ClO2g) O2g ClO2g) O(g ClO(g) ...
23 Aug 2021Moseley established the concept of atomic number by studying X rays emitted by the elements. The X rays emitted by some of the elements have the following wavelengths:a) Calculate the frequency, v, of the X rays emitted by each of the elements, in Hz. (b) Plot the square root of ...
23 Aug 2021In the Millikan oil–drop experiment (see Figure 2.5) the tiny oil drops are observed through the viewing lens as rising, stationary, or falling, as shown here. (a) What causes their rate of fall to vary from their rate in the absence of an electric field? (b) Why do some drops mo...
23 Aug 2021What are the similarities and differences between Figure 20.3 and Figure 20.4? (b) Why are Na ions drawn into the cathode half-cell as the voltaic cell shown in Figure 20.5 operates?One Class Solution:-Figure 20.3 shows spontaneous reaction when a strip of zinc is placed in conta...
23 Aug 2021We have learned in this chapter that many ionic solids dissolve in water as strong electrolytes; that is, as separated ions in solution. Which statement is most correct about this process? (a) Water is a strong acid and therefore is good at dissolving ionic solids. (b) Water is g...
23 Aug 2021Name each of the following oxides. Assuming that the compounds are ionic, what charge is associated with the metallic element in each case? (a) NiO, (b) MnO2c) Cr2O3d) MoO3
23 Aug 2021Both Jacques Charles and Joseph Louis Guy-Lussac were avid balloonists. In his original flight in 1783, Jacques Charles used a balloon that contained approximately 31,150 L of H2. He generated the H2 using the reaction between iron and hydrochloric acid:Fe(s) 2 HCl(aq FeCl2aq) ...
23 Aug 2021Consider the titration of 30.0 mL of 0.050 M NH3 with 0.025 M HCl. Calculate the pH after the following volumes of titrant have been added: (a) 0 mL, (b) 20.0 mL, (c) 59.0 mL, (d) 60.0 mL, (e) 61.0 mL, (f) 65.0 mL.
23 Aug 2021Calculate the mass of octane, C8H18l), that must be burned in air to evolve the same quantity of energy as produced by the fusion of 1.0 g of hydrogen in the following fusion reaction:4 2 Assume that all the products of the combustion of octane are in their gas phases. Use data...
23 Aug 2021Consider the mixture of propane, C3H8, and O2 shown below. (a) Write a balanced equation for the combustion reaction that occurs between propane and oxygen. (b) Which reactant is the limiting reactant? (c) How many molecules of CO2, H2O, C3H8, and O2 will be present if the reacti...
23 Aug 2021What are the differences in the compositions of the following pairs of atomic nuclei? (ab(c)
23 Aug 2021a) What is the mass percentage of iodine in a solution containing 0.035 mol I2 in 125 g of CCl4b) Seawater contains 0.0079 g of Sr2 per kilogram of water. What is the concentration of Sr2 in ppm?b)
23 Aug 2021Gaseous iodine pentafluoride, IF5, can be prepared by the reaction of solid iodine and gaseous fluorine:I2s) 5 F2g 2 IF5gA 5.00-L flask containing 10.0 g of I2 is charged with 10.0 g of F2, and the reaction proceeds until one of the reagents is completely consumed. After the rea...
23 Aug 2021What properties of CFCs make them ideal for various commercial applications but also make them a long-term problem in the stratosphere?
23 Aug 2021It is possible to convert radiant energy into electrical energy using photovoltaic cells. Assuming equal efficiency of conversion, would infrared or ultraviolet radiation yield more electrical energy on a per-photon basis?
23 Aug 2021Consider the mixture of ethanol, C2H5OH, and O2 shown in the accompanying diagram. (a) Write a balanced equation for the combustion reaction that occurs between ethanol and oxygen. (b) Which reactant is the limiting reactant? (c) How many molecules of CO2, H2O, C2H5OH, and O2 wil...
23 Aug 2021Predict whether each of the following oxides is ionic or molecular: SnO2, Al2O3, CO2, Li2O, Fe2O3, H2O.
23 Aug 2021Alcohol-based fuels for automobiles lead to the production of formaldehyde (CH2O) in exhaust gases. Formaldehyde undergoes photodissociation, which contributes to photochemical smog:CH2O hν CHO HThe maximum wavelength of light that can cause this reaction is 335 nm. (a) In wha...
23 Aug 2021For each statement, indicate whether it is true or false. (a) The solubility of a slightly soluble salt can be expressed in units of moles per liter. (b) The solubility product of a slightly soluble salt is simply the square of the solubility.(c) The solubility of a slightly so...
23 Aug 2021You are working with an artist who has been commissioned to make a sculpture for a big city in the eastern United States. The artist is wondering what material to use to make her sculpture because she has heard that acid rain in the eastern United States might destroy it over tim...
23 Aug 2021How many of the indicated atoms are represented by each chemical formula: (a) carbon atoms in C4H8COOCH3b) oxygen atoms in Ca(ClO32c) hydrogen atoms in (NH42HPO4
23 Aug 2021Provide the name or chemical formula, as appropriate, for each of the following acids: (a) hydroiodic acid, (b) chloric acid, (c) nitrous acid, (d) H2CO3e) HClO4f) CH3COOH.
23 Aug 2021Why does the quantum mechanical description of manyelectron atoms make it difficult to define a precise atomic radius? (b) When nonbonded atoms come up against one another, what determines how closely the nuclear centers can approach?
23 Aug 2021How many milliliters of 0.0850 M NaOH are required to titrate each of the following solutions to the equivalence point: (a) 40.0 mL of 0.0900 M HNO3(b) 35.0 mL of 0.0850 M CH3COOH, (c) 50.0 mL of a solution that contains 1.85 g of HCl per liter?
23 Aug 2021A classmate of yours is convinced that he knows everything about electronegativity. (a) In the case of atoms X and Y having different electronegativities, he says, the diatomic molecule X – Y must be polar. Is your classmate correct? (b) Your classmate says that the farther the t...
23 Aug 2021In the formate ion, HCO2, the carbon atom is the central atom with the other three atoms attached to it. (a) Draw a Lewis structure for the formate ion. (b) What hybridization is exhibited by the C atom? (c) Are there multiple equivalent resonance structures for the ion? (d) Whic...
23 Aug 2021At 28 °C, raw milk sours in 4.0 h but takes 48 h to sour in a refrigerator at 5 °C. Estimate the activation energy in kJ/mol for the reaction that leads to the souring of milk?
23 Aug 2021