Ozone in the upper atmosphere can be destroyed by the following two-step mechanism:Cl(g) O3g ClO(g) O2g ClO(g) O(g Cl(g) O2ga) What is the overall equation for this process? (b) What is the catalyst in the reaction? (c) What is the intermediate in the reaction?
22 Aug 2021An 8.65-g sample of an unknown group 2A metal hydroxide is dissolved in 85.0 mL of water. An acid–base indicator is added and the resulting solution is titrated with 2.50 M HCl(aq) solution. The indicator changes color signaling that the equivalence point has been reached after 5...
22 Aug 2021Match the following descriptions of titration curves with the diagrams: (a) strong acid added to strong base, (b) strong base added to weak acid, (c) strong base added to strong acid, (d) strong base added to polyprotic acid.
22 Aug 2021Identify each of the following as measurements of length, area, volume, mass, density, time, or temperature: (a) 25 ps, (b) 374.2 mg, (c) 77 K, (d) 100,000 km2 (e) 1.06 mm, (f) 16 nm2(g) -78 °C, (h) 2.56 g/cm3i) 28 cm3
22 Aug 2021The water supply for a midwestern city contains the following impurities: coarse sand, finely divided particulates, nitrate ion, trihalomethanes, dissolved phosphorus in the form of phosphates, potentially harmful bacterial strains, dissolved organic substances. Which of the foll...
22 Aug 2021Magnesium ions are removed in water treatment by the addition of slaked lime, Ca(OH)2. Write a balanced chemical equation to describe what occurs in this process.
22 Aug 2021The liquid substances mercury (density = 13.6 g/mL), water (1.00 g/mL), and cyclohexane (0.778 g/mL) do not form a solution when mixed but separate in distinct layers. Sketch how the liquids would position themselves in a test tube.
21 Aug 2021Chlorine has two stable nuclides, 35Cl and 37Cl. In contrast, 36Cl is a radioactive nuclide that decays by beta emission. (a) What is the product of decay of 36Cl? (b) Based on the empirical rules about nuclear stability, explain why the nucleus of 36Cl is less stable than either...
21 Aug 2021Consider the following system at equilibrium where H° = 87.9 kJ, and Kc = 1.20×10-2, at 500 K. PCl5(g) PCl3(g) Cl2(g) If the VOLUME of the equilibrium system is suddenly increased at constant temperature: The value of Kc A. increases. B. decreases. C. remains the same. The value...
21 Aug 2021Using only the periodic table, arrange each set of atoms in order of increasing radius: (a) Ba, Ca, Na; (b) In, Sn, As; (c) Al, Be, Si.
21 Aug 2021A stellar object is emitting radiation at 3.55 mm. (a) What type of electromagnetic spectrum is this radiation? (b) If a detector is capturing 3.2 × 108 photons per second at this wavelength, what is the total energy of the photons detected in 1.0 hour?
21 Aug 2021Rainwater is acidic because CO2(g) dissolves in the water, creating carbonic acid, H2CO3. If the rainwater is too acidic, it will react with limestone and seashells (which are principally made of calcium carbonate, CaCO3). Calculate the concentrations of carbonic acid, bicarbonat...
21 Aug 2021You are assigned the task of separating a desired granular material with a density of 3.62 g/cm3 from an undesired granular material that has a density of 2.04 g/cm3. You want to do this by shaking the mixture in a liquid in which the heavier material will fall to the bottom and ...
21 Aug 2021Use the acid-dissociation constants in Table 16.3 to arrange these oxyanions from strongest base to weakest: SO42-, CO32-, SO32-, and PO43-
21 Aug 2021Table 10.3 shows that the van der Waals b parameter has units of L/mol. This means that we can calculate the sizes of atoms or molecules from the b parameter. Refer back to the discussion in Section 7.3. Is the van der Waals radius we calculate from the b parameter of Table 10.3 ...
21 Aug 2021In each of the following balanced oxidation–reduction equations, identify those elements that undergo changes in oxidation number and indicate the magnitude of the change in each case.a)2MnO4 (aq) 3S2-(aq) 4H2O (l) → 3S(s) MnO2(s) 8OH(aq)b)4H2O2 (aq) Cl2O7 (g) 3OH(aq) →2ClO...
21 Aug 2021As shown in the accompanying photograph, an electric stove burner on its highest setting exhibits an orange glow. (a) When the burner setting is changed to low, the burner continues to produce heat but the orange glow disappears. How can this observation be explained with referen...
21 Aug 2021a) What is the trend in electronegativity going from left to right in a row of the periodic table? (b) How do electronegativity values generally vary going down a column in the periodic table? (c) True or false: The most easily ionizable elements are the most electronegative.
21 Aug 2021Based on their respective van der Waals constants (Table 10.3), is Ar or CO2 expected to behave more nearly like an ideal gas at high pressures? Explain.
21 Aug 2021The vertices of a tetrahedron correspond to four alternating corners of a cube. By using analytical geometry, demonstrate that the angle made by connecting two of the vertices to a point at the center of the cube is 109.5°, the characteristic angle for tetrahedral molecules.
21 Aug 2021how many mol NH3 are needed to produce 3.67 mol N2?
21 Aug 2021a) If these three balloons are all the same size, what angle is formed between the red one and the green one? (b) If additional air is added to the blue balloon so that it gets larger, will the angle between the red and green balloons increase, decrease, or stay the same? (c) Whi...
21 Aug 2021In the chemical process called electron transfer, an electron is transferred from one atom or molecule to another. (We will talk about electron transfer extensively in Chapter 20.) A simple electron transfer reaction isA(g) A(g Ag) AgIn terms of the ionization energy and electr...
21 Aug 2021a) How many milliliters of a stock solution of 6.0 M HNO3 would you have to use to prepare 110 mL of 0.500 M HNO3b) If you dilute 10.0 mL of the stock solution to a final volume of 0.250 L, what will be the concentration of the diluted solution?
21 Aug 2021The solubility product for Zn(OH)2 is 3.0 × 10-16. The formation constant for the hydroxo complex, Zn(OH)42–, is 4.6 × 1017. What concentration of OH is required to dissolve 0.015 mol of Zn(OH)2 in a liter of solution?
21 Aug 2021The replicate results (mg/L) obtained from calcium determination of a blood sample using atomic absorption spectrophotometry (AAS) and a new colorimetric method were as following: AAS : 11.2, 11.2, 10.6, 11.2, 9.7 and 10.0 Colorimetric : 9.2, 10.5, 9.7, 11.5, 11.6, 9.3, 10.1 and ...
21 Aug 2021What is the pH of a solution that is 2.5 × 10–9M in NaOH? Does your answer make sense? What assumption do we normally make that is not valid in this case?
21 Aug 2021The graph given below shows [H] vs. concentration for an aqueous solution of an unknown substance. (a) Is the substance a strong acid, a weak acid, a strong base, or a weak base? (b) Based on your answer to (a), can you determine the value of the pH of the solution when the conce...
21 Aug 2021(a) What is the difference between chlorofluorocarbons and hydrofluorocarbons? (b) Why are hydrofluorocarbons potentially less harmful to the ozone layer than CFCs?
21 Aug 2021Consider the molecular models shown here, where X represents a halogen atom. (a) If X is the same atom in both molecules, which molecule will be more acidic? (b) Does the acidity of each molecule increase or decrease as the electronegativity of the atom X increases?
21 Aug 2021Why is the fluorine present in chlorofluorocarbons not a major contributor to depletion of the ozone layer? (b) What are the chemical forms in which chlorine exists in the stratosphere following cleavage of the carbon–chlorine bond?
21 Aug 2021The reaction of bromine gas with chlorine gas, shown here, has a Kc value of 7.20 at 200ºC. If a closed vessel was charged with the two reactants, each at an initial concentration of 0.200 M, but with no initial concentration of BrCl, what would be the equilibrium concentration o...
21 Aug 2021For each of the following pairs of semiconductors, which one will have the larger band gap: (a) InP or InAs, (b) Ge or AlP, (c) AgI or CdTe?
21 Aug 2021You have to prepare a pH 3.50 buffer, and you have the following 0.10 M solutions available: HCOOH, CH3COOH, H3PO4, HCOONa, CH3COONa, and NaH2PO4. Which solutions would you use? How many milliliters of each solution would you use to make approximately 1 L of the buffer?
21 Aug 2021Consider the reaction 3 CH4g C3H8g) 2 H2g(a) Using data from Appendix C, calculate ∆G° at 298 K. (b) Calculate ∆G at 298 K if the reaction mixture consists of 40.0 atm of CH4, 0.0100 atm of C3H8g), and 0.0180 atm of H2
21 Aug 2021Phosphorus is present in seawater to the extent of 0.07 ppm by mass. Assuming that the phosphorus is present as dihydrogenphosphate, H2PO4, calculate the corresponding molar concentration of phosphate in seawater.
21 Aug 2021The element gallium (Ga) freezes at 29.8 °C, and its molar enthalpy of fusion is ∆Hfus = 5.59 kJ/mol. (a) When molten gallium solidifies to Ga(s) at its normal melting point, is ∆S positive or negative? (b) Calculate the value of ∆S when 60.0 g of Ga(l) solidifies at 29.8 °C.
21 Aug 2021How does one determine the number of electron domains in a molecule or ion? (b) What is the difference between a bonding electron domain and a nonbonding electron domain
21 Aug 2021List the following aqueous solutions in order of decreasing freezing point: 0.040 m glycerin (C3H8O3), 0.020 m KBr, 0.030 m phenol (C6H5OH).
21 Aug 2021Suppose that, in the absence of a catalyst, a certain biochemical reaction occurs x times per second at normal body temperature (37 °C). In order to be physiologically useful, the reaction needs to occur 5000 times faster than when it is uncatalyzed. By how many kJ/mol must an en...
21 Aug 2021The phosphorus trihalides (PX3) show the following variation in the bond angle X–P–X: PF3, 96.3°; PCl3, 100.3°; PBr3, 101.0°; PI3, 102.0°. The trend is generally attributed to the change in the electronegativity of the halogen. (a) Assuming that all electron domains are the same ...
21 Aug 2021Two compounds are isomers if they have the same chemical formula but different arrangements of atoms. Use Table 8.4 to estimate ∆H for each of the following gas-phase isomerization reactions and indicate which isomer has the lower enthalpy.
21 Aug 2021When a 4.25-g sample of solid ammonium nitrate dissolves in 60.0 g of water in a coffee-cup calorimeter (Figure 5.17), the temperature drops from 22.0 to 16.9 °C. Calculate ∆H (in kJ/mol NH4NO3) for the solution process:NH4NO3s NH4aq) NO3aqAssume that the specific heat of the so...
21 Aug 2021From their Lewis structures, determine the number of σ and π bonds in each of the following molecules or ions: (a) CO2b) cyanogen, (CN)2c) formaldehyde, H2CO; (d) formic acid, HCOOH, which has one H and two O atoms attached to C.
21 Aug 2021The activation energy of an uncatalyzed reaction is 95 kJ/mol. The addition of a catalyst lowers the activation energy to 55 kJ/mol. Assuming that the collision factor remains the same, by what factor will the catalyst increase the rate of the reaction at (a) 25 °C, (b) 125 °C?Su...
21 Aug 2021A watch with a liquid crystal display (LCD) does not function properly when it is exposed to low temperatures during a trip to Antarctica. Explain why the LCD might not function well at low temperature.
21 Aug 2021A flask is charged with 1.500 atm of N2O4g) and 1.00 atm NO2g) at 25 °C, and the following equilibrium is achieved:N2O4g 2 NO2gAfter equilibrium is reached, the partial pressure of NO2 is 0.512 atm. (a) What is the equilibrium partial pressure of N2O4(b) Calculate the value of Kp...
21 Aug 2021For each pair of compounds, use Ksp values to determine which has the greater molar solubility: (a) CdS or CuS, (b) PbCO3 or BaCrO4c) Ni(OH)2 or NiCO3d) AgI or Ag2SO4
21 Aug 2021The rate of disappearance of HCl was measured for the following reaction:CH3OH(aq) HCl(aq CH3Cl(aq) H2O(lThe following data were collected:a) Calculate the average rate of reaction, in M/s, for the time interval between each measurement. (b) Calculate the average rate of reacti...
21 Aug 2021Does the entropy of the system increase, decrease, or stay the same when (a) the temperature of the system increases, (b) the volume of a gas increases, (c) equal volumes of ethanol and water are mixed to form a solution?
21 Aug 2021