GEN CHEM 1 SI HANDOUT LEADER: Sanjay Srikanth DATE: 11/5/2020 (All time limits are subject to change) Exam 4 Review (65 min) 1. What are the smallest, whole number of stoichiometric coefficients required to balance the following equation? C3H8O (l) + O2 (g) → CO2 (g) + H2O (l) 2. In the following reaction, how many grams of oxygen are required to produce 76.9 grams of water? C3H7SH + O2 → CO2 + SO2 + H2O 3. Determine the limiting reactant and the mass of nitrogen gas that can be formed given 50.0 g N2O4 (molar mass = 92.02 g mol-1) and 45.0 g N2H4 (molar mass = 32.05 g mol-1 N2O4 + N2H4 → N2 + H2O 4. Which of the following is a strong acid? HI HClO3 HF HBr 5. Which of the following are weak electrolytes? HClO2 HNO2 NH3 AgNO3 6. Which of the following will result in a precipitation reaction? a.) Cu(NO3)2 + Na2CO3 b.) NaClO4 + (NH4)2S c.) K2SO4 + Cu(NO3)2 d.) NH4Br + NaI e.) None of the above 7. Write the net ionic equation for the reaction of CaCl2 and Na2SO4 8. Write the net ionic equation for the reaction of aluminum acetate and lithium nitrate. 9. Which of the following reactants will undergo a reaction (if any)? I. Na (s) + Fe2+ (aq) II. Cd (s) + Ba2+ (aq) III. K (s) + Li+ (aq) IV. Sn (s) + Cu2+ (aq) V. Zn (s) + Mn2+ (aq) 10. Balance the following equation: Cr (s) + Cu2+ (aq) → Cu (s) + Cr3+ (aq) 11. The spectator ions in the aqueous reaction between HCl and NH3 is/are: 12. What is the theoretical yield (in moles) of H2S if 5 mol Al2S3 and 5 mol H2O are reacted according to the following unbalanced equation? Al2S3 (s) + H2O (l) → Al(OH)3 + H2S 13. Determine the percent yield of Fe if 28.65 g of Fe are produced when 50.0g of Fe2O3 reacts with 20.0 g of Al. Fe2O3 + 2Al → Al2O3 + 2Fe 14. Write the balanced molecular formula for the reaction of ammonia and sulfuric acid. 15. Write the net ionic equation for the reaction of chloric acid and calcium hydroxide. 16. Write the net ionic equation for the reaction of phosphoric acid and potassium hydroxide. 17. Determine the oxidation number of P in PO33- 18. Determine the oxidation number of O in K2O2 19. What species is the oxidizing agent in the following equation? 2Li (s) + Fe(C2H3O2)2 (aq) → Li(C2H3O2) (aq) + Fe (s) A.) Fe B.) Fe(C2H3O2)2 C.) Li D.) Li(C2H3O2) E.) C2H3O2- 20. A 50 mL sample of 0.436 M NH4NO3 is diluted by adding 250 mL of water. What is the final concentration of the ammonium nitrate solution? 21. Calculate the final bromide ion concentration if we combine 23.4 mL of a 2.7 M HBr solution with 31.3 mL of a 0.25 M AlBr3 solution, and diluted to 150 mL. 22. What is the pH of a 5.65 x 10^-10 M solution of hydroiodic acid? 23. A 5.234 gram sample of MgCl2 is dissolved in 134 mL of water. What is the concentration of chloride ions in the solution? 24. In a titration experiment, a student finds that 15.49 mL of a NaOH solution is needed to neutralize 0.637 g of KHP (molar mass: 204.2 g mol-1), a monoprotic acid. What is the concentration (in M) of the NaOH solution? 25. What volume (in mL) of a 0.312 M NaOH solution is needed to completely neutralize 35.0 mL of a 0.281 M H2SO4 solution? 26. A 0.1216-g sample of a monoprotic acid is dissolved in 25 mL water, and the resulting solution is titrated with 0.1104 M NaOH solution. A 12.5-mL volume of the base is required to neutralize the acid. Calculate the molar mass of the acid. 27. When heat is absorbed by the surroundings and work is done by the system, what are the signs of q (heat) and w (work)? 28. When a reaction is endothermic, what is the value of delta H? 29. What is the overall potential energy change in a system that absorbs 209 J of heat and does 322 J of work on its surroundings. 30. Assuming that, for a reaction, delta U is -4.12 x 103 kJ and 437 kJ of heat is released. How much work is done, and is the work done by the system or on the system 31. Given the thermochemical equation 2SO2 + O2 → 2SO3 ΔHrxn = -198 kJ/mol What is the energy change for the reaction of 3.5 mol SO2 (excess O2)? 32. Given the thermochemical equation for photosynthesis: 6H2O + 6CO2 → C6H12O6 + 6O2 ΔHrxn = +2803 kJ/mol Find how much energy is required to produce 75 grams of C6H12O6 (glucose) (180.2 g mol-1) . 33. No question, just a friendly reminder about some thermochem equations/concepts: ΔU = q + w w = -PΔV WHEN V IS CONSTANT q = ΔU WHEN P IS CONSTANT q = ΔU + PΔV ΔH = ΔU + PΔV AT CONSTANT PRESSURE: ΔH = q ΔHrxn = ΔHproducts - ΔHreactants State functions: Only depends on the initial and final state First law of thermodynamics: Usys + Usurr = 0 (energy cannot be created or destroyed)
