Thermodynamics & Chemical Reactions: Entropy, Heat, & Equilibrium Constants, Exercises of Chemistry

Download Thermodynamics & Chemical Reactions: Entropy, Heat, & Equilibrium Constants and more Exercises Chemistry in PDF only on Docsity! 1. (8 points) Which system has the greater entropy in each case? NH3(g) or NCl3(l) liquid water at 0 °C or solid water at 0 °C KClO3(s) at 22 °C or KClO3(aq) at 22 °C Hexane or 2,5-dimethylhexane 2. (8 points) Predict the sign of the entropy change associated with each process: CO2(g) → CO2(aq) (at 298 K and 1 atm) Cu(s) at 350 K → Cu(s) at 300 K CaCO3(s) + heat → CaO(s) + CO2(g) NH3(g) + HBr(g) → NH4Br(s) 3. (4 points) Name an acid/salt combinations (i.e. acetic acid/sodium acetate) that would be useful in making a buffer solution whose pH is approximately 6.7. Docsity.com 4. (12 points) Use the information included on the back of your periodic table to determine the value of ΔGorxn and to calculate the equilibrium constant for the following reaction at 600 K. SnO2(s) + C(graphite) ↔ Sn(s) + CO2(g) 5. (8 points) A solution is prepared by mixing 150. mL of 0.110 M benzoic acid and 1.38 grams of sodium benzoate (NaC6H5CO2) – determine its pH. Docsity.com 10. (9 points) What mass of lead (II) fluoride, PbF2, can be dissolved in 1.00 L of a 0.0800 M solution of lead (II) nitrate, Pb(NO3)2? The Ksp of PbF2 is 3.3×10-8. 11. (9 points) A solution of calcium phosphate is prepared by dissolving some Ca3(PO4)2 ina beaker of water. What is the Ksp of calcium phosphate if spectrophotometric analysis of the solution determines the concentration of calcium ions is 2.34×10-4 M? Docsity.com Thermodynamic Data Compound S o (J/mol·K) ΔHof (kJ/mol) HCl(aq) 55.06 -167.5 MgCl2(s) 89.63 -641.6 H2O(g) 188.7 -241.8 H2O(l) 69.94 -285.8 CO2(g) 213.7 -393.5 CO(g) 197.5 -110.5 H2(g) 130.6 0 CH3OH(g) 238.0 -201.2 CuS(s) 66.5 -53.1 MgO(s) 26.9 -601.2 C(graphite) 5.7 0 Cu(s) 33.1 0 Sn(s) 51.5 0 SnO2(s) 52.3 -580.7 Docsity.com