Which of the following schematic drawings best describes a solution of Li2SO4 in water (water molecules not shown for simplicity)?
23 Aug 2021What is the function of the control rods in a nuclear reactor? What substances are used to construct control rods? Why are these substances chosen?
23 Aug 2021The accompanying drawing shows part of the orbital diagram for an element. (a) As drawn, the drawing is incorrect. Why? (b) How would you correct the drawing without changing the number of electrons? (c) To which group in the periodic table does the element belong?
23 Aug 2021which of the following substituents has the highest priority
23 Aug 2021Common laboratory solvents include acetone (CH3COCH3), methanol (CH3OH), toluene (C6H5CH3), and water. Which of these is the best solvent for nonpolar solutes?
23 Aug 2021(a) Which of the following ionic species could be responsible for hardness in a water supply: Ca2, K, Mg2, Fe2, Na(b) What properties of an ion determine whether it will contribute to water hardness?
23 Aug 2021One of the attractive features of ionic liquids is their low vapor pressure, which in turn tends to make them nonflammable. Why do you think ionic liquids have lower vapor pressures than most room-temperature molecular liquids?
23 Aug 2021Explain why an increasing concentration of CO2 in the atmosphere affects the quantity of energy leaving Earth but does not affect the quantity of energy entering from the Sun.
23 Aug 2021Which of the following nuclides have magic numbers of both protons and neutrons: (a) helium-4, (b) oxygen-18, (c) calcium-40, (d) zinc-66, (e) lead-208?
23 Aug 2021Carotenoids are yellow, orange, and red pigments synthesized by plants. The observed color of an object is not the color of light it absorbs but rather the complementary color, as described by a color wheel such as the one shown here. On this wheel, complementary colors are acros...
23 Aug 2021At the freezing point of water (0 °C), Kw = 1.2 × 10-15. Calculate [H] and [OH] for a neutral solution at this temperature.
23 Aug 2021The following is known as the thermite reaction:2 Al(s) Fe2O3s Al2O3s) 2 Fe(sThis highly exothermic reaction is used for welding massive units, such as propellers for large ships. Using standard enthalpies of formation in Appendix C, calculate ∆H° for this reaction.
23 Aug 2021A mixture of N2g) and H2g) reacts in a closed container to form ammonia, NH3g). The reaction ceases before either reactant has been totally consumed. At this stage 3.0 mol N2, 3.0 mol H2, and 3.0 mol NH3 are present. How many moles of N2 and H2 were present originally?
23 Aug 2021Two patterns of packing for two different spheres are shown here. For each structure (a) draw the two-dimensional unit cell; (b) determine the angle between the lattice vectors, γ, and determine whether the lattice vectors are of the same length or of different lengths; and (c) d...
23 Aug 2021a) What is a functional group? (b) What functional group characterizes an alcohol? (c) Write a structural formula for 1-pentanol, the alcohol derived from pentane by making a substitution on one of the carbon atoms.
23 Aug 2021Consider the combustion of a single molecule of CH4g), forming H2O(l) as a product. (a) How much energy, in J, is produced during this reaction? (b) A typical X-ray light source has an energy of 8 keV. How does the energy of combustion compare to the energy of the X-ray?
23 Aug 2021The Ogallala aquifer described in the Closer Look box in Section 18.3, provides 82% of the drinking water for the people who live in the region, although more than 75% of the water that is pumped from it is for irrigation. Irrigation withdrawals are approximately 18 billion gallo...
23 Aug 2021When is added to at in a calorimeter, the temperature of the aqueous solution increases to . Assuming that the specific heat of the solution is , that its density is , and that the calorimeter itself absorbs a negligible amount of heat, calculate the amount of heat absorbe...
23 Aug 2021Using the value of Ksp for Ag2S, Ka1 and Ka2 for H2S, and Kf = 1.1 × 105 for AgCl2, calculate the equilibrium constant for the following reaction:Ag2S(s) 4 Claq) 2 Haq 2 AgCl2aq) H2S(aq
23 Aug 2021Calculate the solubility of silver carbonate in a solution buffered to pH 6.540. Report your answer as log s.
23 Aug 2021The total rate at which power used by humans worldwide is approximately 15 TW (terawatts). The solar flux averaged over the sunlit half of Earth is 680 W/m2. (assuming no clouds). The area of Earth’s disc as seen from the sun is 1.28 1014 m2. The surface area of Earth is approxi...
23 Aug 2021Using only the periodic table, arrange each set of atoms in order from largest to smallest: (a) K, Li, Cs; (b) Pb, Sn, Si; (c) F, O, N.
23 Aug 2021The average adult male has a total blood volume of 5.0 L. After drinking a few beers, he has a BAC of 0.10 (see Exercise 4.65). What mass of alcohol is circulating in his blood?
23 Aug 2021The molecule n-octylglucoside, shown here, is widely used in biochemical research as a nonionic detergent for “solubilizing” large hydrophobic protein molecules. What characteristics of this molecule are important for its use in this way?
23 Aug 2021After the completion of a gas forming reaction, the column of water remaining in the collection flask was measured to me high, the vapor pressure of water is at , and the atmospheric pressure that day was measured as , what is the partial pressure of the gas produced by the rea...
23 Aug 2021The osmotic pressure of a 0.010 M aqueous solution of CaCl2 is found to be 0.674 atm at 25 °C. (a) Calculate the van’t Hoff factor, i, for the solution. (b) How would you expect the value of i to change as the solution becomes more concentrated? Explain.
23 Aug 2021The hydrogen atom can absorb light of wavelength 1094 nm. (a) In what region of the electromagnetic spectrum is this absorption found? (b) Determine the initial and final values of n associated with this absorption.
23 Aug 2021Which property of the group 6A elements might be the one depicted in the graph shown here: (a) electronegativity, (b) first ionization energy, (c) density, (d) X–X single-bond enthalpy, (e) electron affinity? Explain your answer.
23 Aug 2021Potassium-40 decays to argon-40 with a half-life of 1.27 × 109 yr. What is the age of a rock in which the mass ratio of 40Ar to 40K is 4.2?
23 Aug 2021(a) If QcKc, how must the reaction proceed to reach equilibrium? (b) At the start of a certain reaction, only reactants are present; no products have been formed. What is the value of Qc at this point in the reaction?
23 Aug 2021The density of a gas of unknown molar mass was measured as a function of pressure at 0 °C, as in the table that follows. (a) Determine a precise molar mass for the gas. [Hint: Graph dP versus Pb) Why is dP not a constant as a function of pressure?
23 Aug 2021Consider the Lewis structure shown below.a) Does the Lewis structure depict a neutral molecule or an ion? If it is an ion, what is the charge on the ion? (b) What hybridization is exhibited by each of the carbon atoms? (c) Are there multiple equivalent resonance structures for th...
23 Aug 2021Magnesium metal is used as a sacrificial anode to protect underground pipes from corrosion. Why is the magnesium referred to as a “sacrificial anode”? (b) Looking in Appendix E, suggest what metal the underground pipes could be made from in order for magnesium to be successful as...
23 Aug 2021Federal regulations set an upper limit of 50 parts per million (ppm) of NH3 in the air in a work environment [that is, 50 molecules of NH3g) for every million molecules in the air]. Air from a manufacturing operation was drawn through a solution containing 1.00 × 102 mL of 0.0105...
23 Aug 2021When a mixture of 10.0 g of acetylene (C2H2) and 10.0 g of oxygen (O2) is ignited, the resultant combustion reaction produces CO2 and H2O. (a) Write the balanced chemical equation for this reaction. (b) Which is the limiting reactant? (c) How many grams of C2H2, O2, CO2, and H2O ...
23 Aug 2021For many years drinking water has been cooled in hot climates by evaporating it from the surfaces of canvas bags or porous clay pots. How many grams of water can be cooled from 35 to 20 °C by the evaporation of 60 g of water? (The heat of vaporization of water in this temperature...
23 Aug 2021Use electron configurations to explain the following observations: (a) The first ionization energy of phosphorus is greater than that of sulfur. (b) The electron affinity of nitrogen is lower (less negative) than those of both carbon and oxygen. (c) The second ionization energy o...
23 Aug 2021The standard potential for the reduction of AgSCN(s) is 0.0895 V.AgSCN(s) e Ag(s) SCNaqUsing this value and the electrode potential for Agaq),calculate the Ksp for AgSCN.
23 Aug 2021Write the condensed electron configurations for the following atoms, using the appropriate noble-gas core abbreviations: (a) Mg, (b) Ge, (c) Br, (d) V, (e) Y, (f) Lu.
23 Aug 2021How did Rutherford interpret the following observations made during his α-particle scattering experiments? (a) Most a particles were not appreciably deflected as they passed through the gold foil. (b) A few a particles were deflected at very large angles. (c) What differences wou...
23 Aug 2021A 0.25 M solution of a salt NaA has pH = 9.29. What is the value of Ka for the parent acid HA?
23 Aug 2021Hydrogen cyanide is a highly poisonous, volatile liquid. One way in which it can be prepared is by the reaction: CH4 (g) NH3 (g) → HCN (g) 3 H2 (g) Use Hess’ law and the following thermochemical equations to find the heat of the above reaction at constant pressure.N2 (g) 3 H2 ...
23 Aug 2021Pure iron crystallizes in a body-centered cubic structure, but small amounts of impurities can stabilize a face-centered cubic structure. Which form of iron has a higher density?
23 Aug 2021Based on the data in Appendix E, (a) which of the following is the strongest oxidizing agent and which is the weakest in acidic solution: Br2, H2O2, Zn, Cr2O72 -(b) Which of the following is the strongest reducing agent, and which is the weakest in acidic solution: F, Zn, N2H5, I...
23 Aug 2021The element oxygen has three naturally occurring isotopes, with 8, 9, and 10 neutrons in the nucleus, respectively. (a) Write the full chemical symbols for these three isotopes. (b) Describe the similarities and differences between the three kinds of atoms of oxygen.
23 Aug 2021An important reaction in the formation of photochemical smog is the photodissociation of NO2NO2hν NO(g) O(g The maximum wavelength of light that can cause this reaction is 420 nm. (a) In what part of the electromagnetic spectrum is light with this wavelength found? (b) What is...
23 Aug 2021In chemical kinetics the entropy of activation is the entropy change for the process in which the reactants reach the activated complex. The entropy of activation for bimolecular processes is usually negative. Explain this observation with reference to Figure 14.15.
23 Aug 2021The fat stored in a camel’s hump is a source of both energy and water. Calculate the mass of H2O produced by the metabolism of 1.0 kg of fat, assuming the fat consists entirely of tristearin (C57H110O6), a typical animal fat, and assuming that during metabolism, tristearin reacts...
23 Aug 2021The methane molecule, CH4, has the geometry shown in Figure 2.17. Imagine a hypothetical process in which the methane molecule is “expanded,” by simultaneously extending all four C—H bonds to infinity. We then have the processCH4g C(g) 4 H(ga) Compare this process with the rever...
23 Aug 2021a) The world population is estimated to be approximately 7 billion people. How many moles of people are there? (b) What units are typically used to express formula weight? (c) What units are typically used to express molar mass?
23 Aug 2021