A lithium salt used in lubricating grease has the formula LiCnH2n 1O2. The salt is soluble in water to the extent of 0.036 g per 100 g of water at 25 °C. The osmotic pressure of this solution is found to be 57.1 torr. Assuming that molality and molarity in such a dilute solution...
22 Aug 2021a) What experimental evidence is there for the electron having a “spin”? (b) Draw an energy-level diagram that shows the relative energetic positions of a 1s orbital and a 2s orbital. Put two electrons in the 1s orbital. (c) Draw an arrow showing the excitation of an electron fro...
22 Aug 2021A 25.0-cm long cylindrical glass tube, sealed at one end, is filled with ethanol. The mass of ethanol needed to fill the tube is found to be 45.23 g. The density of ethanol is 0.789 g/mL. Calculate the inner diameter of the tube in centimeters.
22 Aug 2021A buffer contains 0.10 mol of acetic acid and 0.13 mol of sodium acetate in 1.00 L. (a) What is the pH of this buffer? (b) What is the pH of the buffer after the addition of 0.02 mol of KOH? (c) What is the pH of the buffer after the addition of 0.02 mol of HNO3
22 Aug 2021Student added 20 drops of unknown halide in a TT, followed by the addition of AgNO3 in the same TT. Shake the TT and add NH3 in the same TT, again shake the TT. Centrifuge the TT, and take supernatent into a clean TT. In this supernatent, add 5 drops of HNO3 and there was a preci...
22 Aug 2021What are the basic SI units for (a) the wavelength of light, (b) the frequency of light, (c) the speed of light?
22 Aug 2021What is an electrolytic cell? (b) The negative terminal of a voltage source is connected to an electrode of an electrolytic cell. Is the electrode the anode or the cathode of the cell? Explain. (c) The electrolysis of water is often done with a small amount of sulfuric acid added...
22 Aug 2021The standard reduction potential for the reduction of Eu3(aq) to Eu2(aq) is -0.43 V. Using Appendix E, which of the following substances is capable of reducing Eu3(aq) to Eu2(aq) under standard conditions: Al, Co, H2O2, N2H5, H2C2O4
22 Aug 2021Assume that 30.0 mL of a 0.10 M solution of a weak base B that accepts one proton is titrated with a 0.10 M solution of the monoprotic strong acid HA. (a) How many moles of HA have been added at the equivalence point? (b) What is the predominant form of B at the equivalence point...
22 Aug 2021Repeat Exercise 12.47 for a linear chain of eight lithium atoms.
22 Aug 2021The effectiveness of nitrogen fertilizers depends on both their ability to deliver nitrogen to plants and the amount of nitrogen they can deliver. Four common nitrogen-containing fertilizers are ammonia, ammonium nitrate, ammonium sulfate, and urea [(NH22CO] Rank these fertilizer...
22 Aug 2021a) Using the electronegativities of Br and Cl, estimate the partial charges on the atoms in the Br – Cl molecule. (b) Using these partial charges and the atomic radii given in Figure 7.8, estimate the dipole moment of the molecule. (c) The measured dipole moment of BrCl is 0.57 D...
22 Aug 2021Consider the following system at equilibrium at 698 K: 2HI(g) H2(g) I2(g) When some H2(g) is added to the equilibrium system at constant temperature: The reaction must: A. Run in the forward direction to reestablish equilibrium. B. Run in the reverse direction to reestablish e...
22 Aug 2021What is the effect on the emf of the cell shown in Figure 20.9, which has the overall reaction Zn(s) 2H(aq)→Zn2(aq) H2(g), for each of the following changes?(a) The pressure of the H2 gas is increased in the cathode halfcell.(b) Zinc nitrate is added to the anode half-cell. (c)...
22 Aug 2021Mixtures of helium and oxygen are used in scuba diving tanks to help prevent "the bends". For a particular dive, 18.6 L of oxygen gas at and 1.79 atm, and 7.55 L of helium gas at and 2.68 atm were pumped into a tank with a volume of 6.00 L at Calculate (in atm):1. the partial p...
22 Aug 2021Oil and water are immiscible. Which is the most likely reason? (a) Oil molecules are denser than water. (b) Oil molecules are composed mostly of carbon and hydrogen. (c) Oil molecules have higher molar masses than water. (d) Oil molecules have higher vapor pressures than water. (...
22 Aug 2021For the table that follows, write which orbital goes with the quantum numbers. Don’t worry about xyz subscripts. If the quantum numbers are not allowed, write “not allowed.” N1m1Orbital21-12p (example)1003-3232-220-1000421530
22 Aug 2021Which of the following reactions in the stratosphere cause an increase in temperature there?(a) O(g) O2g O3g (b) O3g) M(g O3g) M*(g (c) O2ghυ 2 O(g (d) O(g) N2g NO(g) N(g (e) All of the above
22 Aug 2021A face-centered tetragonal lattice is not one of the 14 three-dimensional lattices. Show that a face-centered tetragonal unit cell can be redefined as a body-centered tetragonal lattice with a smaller unit cell.
22 Aug 2021Are gases always miscible with each other? Explain
22 Aug 2021Epsom salts, a strong laxative used in veterinary medicine, is a hydrate, which means that a certain number of water molecules are included in the solid structure. The formula for Epsom salts can be written as MgSO4xH2O, where x indicates the number of moles of H2O per mole of Mg...
22 Aug 2021Consider the following equilibrium:2 H2g) S2g 2 H2S(gKc = 1.08 × 107at 700 °Ca) Calculate Kp(b) Does the equilibrium mixture contain mostly H2 and S2 or mostly H2S? (c) Calculate the value of Kc if you rewrote the equation H2g S2g H2S(g
22 Aug 2021The element lead (Pb) consists of four naturally occurring isotopes with atomic masses 203.97302, 205.97444, 206.97587, and 207.97663 amu. The relative abundances of these four isotopes are 1.4, 24.1, 22.1, and 52.4% respectively. From these data, calculate the atomic weight of l...
22 Aug 2021(a) What is meant by the term isomer? (b) Among the four alkanes, ethane, propane, butane, and pentane, which is capable of existing in isomeric forms?
22 Aug 2021Propane, C3H8, liquefies under modest pressure, allowing a large amount to be stored in a container. (a) Calculate the number of moles of propane gas in a 110-L container at 3.00 atm and 27 °C. (b) Calculate the number of moles of liquid propane that can be stored in the same vol...
22 Aug 2021a) Calculate the molarity of a solution that contains 0.175 mol ZnCl2 in exactly 150 mL of solution. (b) How many moles of protons are present in 35.0 mL of a 4.50 M solution of nitric acid? (c) How many milliliters of a 6.00 M NaOH solution are needed to provide 0.350 mol of NaO...
22 Aug 2021A package of aluminum foil contains 50 ft2 of foil, which weighs approximately 8.0 oz. Aluminum has a density of 2.70 g/cm3. What is the approximate thickness of the foil in millimeters?
22 Aug 2021In which of the following AFn molecules or ions is there more than one F–A–F bond angle: SiF4, PF5, SF4, AsF3
22 Aug 2021Stars do not all have the same temperature. The color of light emitted by stars is characteristic of the light emitted by hot objects. Telescopic photos of three stars are shown below: (i) the Sun, which is classified as a yellow star, (ii) Rigel, in the constellation Orion, whic...
22 Aug 2021It takes 4 h 39 min for a 2.00-mg sample of radium-230 to decay to 0.25 mg. What is the half-life of radium-230?
22 Aug 2021a) Is lattice energy usually endothermic or exothermic? (b) Write the chemical equation that represents the process of lattice energy for the case of NaCl. (c) Would you expect salts like NaCl, which have singly-charged ions, to have larger or smaller lattice energies compared to...
22 Aug 2021The reaction of three molecules of fluorine gas with a Xe atom produces the substance xenon hexafluoride, XeF6Xe(g) 3 F2g XeF6sa) Draw a Lewis structure for XeF6b) If you try to use the VSEPR model to predict the molecular geometry of XeF6, you run into a problem. What is it? (c...
22 Aug 2021Suppose that a woman weighing 130 lb and wearing high-heeled shoes momentarily places all her weight on the heel of one foot. If the area of the heel is 0.50 in.2, calculate the pressure exerted on the underlying surface in (a) kilopascals, (b) atmospheres, and (c) pounds per squ...
22 Aug 2021At ordinary body temperature (37 °C), the solubility of N2 in water at ordinary atmospheric pressure (1.0 atm) is 0.015 g/L. Air is approximately 78 mol % N2a) Calculate the number of moles of N2 dissolved per liter of blood, assuming blood is a simple aqueous solution. (b) At a ...
22 Aug 2021In each of the following pairs, indicate which has the higher concentration of I ion: (a) 0.10 M BaI2 or 0.25 M KI solution, (b) 100 mL of 0.10 M KI solution or 200 mL of 0.040 M ZnI2 solution, (c) 3.2 M HI solution or a solution made by dissolving 145 g of NaI in water to make 1...
22 Aug 2021Consider the equilibriumN2g) O2g) Br2g
22 Aug 2021Proteins are naturally occurring polymers formed by condensation reactions of amino acids, which have the general structureIn this structure, –R represents –H, –CH3, or another group of atoms; there are 20 different natural amino acids, and each has one of 20 different R groups. ...
22 Aug 2021Acetonitrile (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 concentration of the solution in (a) molality, (b) mole fraction of LiBr, (c) mass per...
22 Aug 2021Write a balanced chemical equation for the reaction that occurs when (a) Mg(s) reacts with Cl2gb) barium carbonate decomposes into barium oxide and carbon dioxide gas when heated; (c) the hydrocarbon styrene, C8H8l), is combusted in air; (d) dimethylether, CH3OCH3g), is combusted...
22 Aug 2021How do the following changes affect the value of the equilibrium constant for a gas-phase exothermic reaction: (a) removal of a reactant, (b) removal of a product, (c) decrease in the volume, (d) decrease in the temperature, (e) addition of a catalyst?
22 Aug 2021A friend of yours has seen each of the following items in newspaper articles and would like an explanation: (a) acid rain, (b) greenhouse gas, (c) photochemical smog, (d) ozone depletion. Give a brief explanation of each term and identify one or two of the chemicals associated wi...
22 Aug 2021Look up the diameter of a silicon atom, in Å. The latest semiconductor chips have fabricated lines as small as 22 nm. How many silicon atoms does this correspond to?
22 Aug 2021What are the electron-domain and molecular geometries of a molecule that has the following electron domains on its central atom? (a) Three bonding domains and no nonbonding domains, (b) three bonding domains and one nonbonding domain, (c) two bonding domains and two nonbonding do...
22 Aug 2021For each of the following elements, write its chemical symbol, determine the name of the group to which it belongs (Table 2.3), and indicate whether it is a metal, metalloid, or nonmetal: (a) potassium, (b) iodine, (c) magnesium, (d) argon, (e) sulfur.
22 Aug 2021The kinetics of microbial growth, substrate consumption and mixed-growth-associated product formation in a chemostat culture are given by the following equations: The kinetic parameter values are and a. Determine the optimal dilution rate maximizing the productivity of product f...
22 Aug 2021a) What molecular features make a polymer flexible? (b) If you cross-link a polymer, is it more flexible or less flexible than it was before?
22 Aug 2021The rate of solar energy striking Earth averages 168 watts per square meter. The rate of energy radiated from Earth’s surface averages 390 watts per square meter. Comparing these numbers, one might expect that the planet would cool quickly, yet it does not. Why not?
22 Aug 2021The coordination number for the Al3 ion is typically between four and six. Use the anion coordination number to determine the Al3 coordination number in the following compounds: (a) AlF3 where the fluoride ions are two coordinate, (b) Al2O3 where the oxygen ions are six coordina...
22 Aug 2021Titanium metal is used as a structural material in many high-tech applications such as jet engines. What is the specific heat of titanium in J/g°C if it takes 89.7 J to raise the temperature of a 33.0 g block by 5.20°C? What is the molar heat capacity of titanium in J/mol °C?
22 Aug 2021Some metal oxides, such as Sc2O3, do not react with pure water, but they do react when the solution becomes either acidic or basic. Do you expect Sc2O3 to react when the solution becomes acidic or when it becomes basic? Write a balanced chemical equation to support your answer.
22 Aug 2021