The equilibrium constant for the reaction
CO(g) + H2O(g) ∏ CO2(g) + H2(g) is K = 1.03 ´ 105 at 298.15 K. Calculate the standard reaction Gibbs energy at this temperature.
Calculate the equilibrium constant at 25 °C for the reaction
2 NO(g) + O2(g) ∏ 2 NO2(g) given that DrGo = –69.8 kJ mol–1.
Calculate the standard reaction Gibbs energy DrGʅ at 298 K for the combustion of ethane
C2H6(g) + 3½ O2(g) ∏ 2 CO2(g) + 3 H2O(l) given that the standard Gibbs energies of formation of the components at this temperature are DfGʅ(C2H6, g) = –32.82 kJ mol–1, DfGʅ (CO2,g) = –394.36 kJ mol–1, DfGʅ(H2O,l) = –237.13 kJ mol–1.
The partial pressure of a component in a gas-phase reaction is 0.452 atm. What is the activity of the component?
The reaction
Si(s) + 2 H2(g) ∏ SiH4(g) is spontaneous at 298 K. The standard enthalpy of reaction DrH° = –61.9 kJ mol–1 and standard entropy of reaction DrSo = –76.7 J K–1 mol–1. At what temperature does the reaction cease to be spontaneous?
When equal amounts of hydrogen, H2, and iodine, I2, are mixed together at a total pressure of 1 bar, the partial pressure of hydrogen iodide, HI, vapour produced from by the reaction
H2(g) + I2(g) ∏ 2 HI(g) is 22.8 kPa. Calculate the equilibrium constant for the reaction.
Calcium carbonate undergoes thermal decomposition
CaCO3(s) ∏ CaO(s) + CO2(g) at high temperatures. The equilibrium constant for the reaction is 0.0120 at 900 K. Calculate the partial pressure of carbon dioxide, CO2, when calcium carbonate, CaCO3, is heated at 900 K.
The equilibrium constant for the gas-phase reaction
N2O4(g) ∏ 2 NO2(g) is 0.1179. Calculate the mole fraction of nitrogen dioxide, NO2, in the equilibrium reaction mixture when the total pressure is exactly 1 bar.
PCl3(g) + Cl2(g) ∏ PCl5(g) is K = 3.29 ´ 106 at 298 K. Calculate the value of Kc, the equilbrium constant expressed in terms of concentrations.
2HCl(g) + O2(g) ∏ H2O(g) + Cl2(g) is 13300 at 400 K and 429 at 500 K. Use the van't Hoff equation to determine the standard enthalpy of reaction.
Calculate the concentration of hydronium, H3O+, ions in a solution of with pH = 4.3.
The standard Gibbs energy of reaction, DrGo, for the dissociation of phenol is 56.4 kJ mol–1 at 298 K. Calculate the pKa of phenol.
The pKa of hypochlorous acid, HClO, is 7.53. What is the value of pKb?
Calculate the concentration of OH– ions in a solution with pH = 12.1.
Calculate the pH of an aqueous solution of hydrocyanic acid of concentration 0.088 mol dm–3. The acidity constant of hydrocyanic acid is 4.9 ´ 10–10.
Calculate the concentration of SO32– ions in an aqueous solution of sulfurous acid, H2SO3. The second acidity constant of sulfurous acid is Ka2 = 1.2 ´ 10–7.
Calculate the pH of an aqueous solution of potassium hydrogensulfite, KHSO3. For sulfurous acid, pKa1 = 1.81 and pKa2 = 6.91.
In a titration, 2.7 cm3 of 0.100 mol dm–3 sodium hydroxide, NaOH, solution is added to 25.0 cm3 of 0.125 mol dm–3 benzoic acid, C6H5COOH, solution. Calculate the pH of the resulting solution given that the pKa of benzoic acid is 4.19.
Use the data in Table 8.1 to estimate the pH of a buffer solution formed from equal amounts of potassium carbonate, K2CO3, and potassium hydrogen carbonate, KHCO3.
Calculate the concentration of chloride ions, Cl–, in an aqueous solution formed by adding lead chloride, PbCl2, to water. The solubility constant of lead chloride is 1.6 ´ 10–5.
Calculate the ionic strength of a solution of iron (III) carbonate, Fe2(CO3)3 of concentration 0.020 mol dm–3.
Use the Debye–Hückel limiting law to calculate the mean activity coefficient for the ions in an aqueous solution of potassium sulfate, K2SO4, of molality 0.010 mol kg–1 at 25°C.
The pKa of hydrocyanic acid, HCN, is 9.218 at 293 K. Calculate the conductivity of an aqueous solution of perchloric acid, of concentration 0.015 mol dm–3, given that the ionic conductivity of H3O+ ions is 35 mS m2 mol–1 and of CN– ions is 82 mS m2 mol–1.
For a galvanic cell, which of the following statements is never true?
The standard reaction Gibbs energy for the electrochemical reaction
Cr2O72– + 2 Fe + 14 H+ ® 2 Cr3+ + 2 Fe3+ 7 H2O
is –793 kJ mol–1. Calculate the standard cell potential.
The standard cell potential for the reaction
Cu2+(aq) + Fe2+(aq) + I–(aq) ∏ CuI(s) + Fe3+(aq) is +0.090 V. Use the Nernst equation to calculate the electrochemical potential at 298.15 K for the cell
Pt(s)│CuI2(aq, 0.010 mol dm–3)│CuI(s)║FeSO4(aq, 0.010 mol dm–3),Fe2(SO4)3(aq, 0.020 mol dm–3)│Pt(s)
Use the data in Table 5J.1 to calculate the standard cell potential for the reaction
Calculate the equilibrium constant for the reaction
S2O82–(aq) + 2 Fe2+(aq) ∏ 2 Fe3+(aq) + 2 SO42–(aq) at 25.0 °C, given that the standard cells potentials for the two half reactions at this temperature are
S2O82–(aq) + 2 e– ∏ 2 SO42–(aq) Eʅ = +2.08 V
Fe3+(aq) + e– ∏ Fe2+(aq) Eʅ = +0.77 V
The standard cell potential for the Daniell cell,
Printed from , all rights reserved. © Oxford University Press, 2024
.png){kind=icon}
