Page 1 of 10 Student ID : _________________________ CH 115 Summer 2014 Mock Exam 2 *** Assume that equations are NOT balanced *** 1. Fill in the blank with the correct letter. 1. ___Work 2. ___Thermodynamics 3. ___System 4. ___ Potential Energy 5. ___Heat capacity 6. ___Surroundings 7. ___Kinetic energy 8. ___ Internal Energy (E) 9. ___Enthalpy (H) a. Energy due to position. b. The energy required to move the temperature of a sample by 1 degree. c. The movement of an object against some force. d. The part of the universe we single out to study in thermodynamics. e. The sum of all kinetic and potential energy of a system. f. Energy due to motion. g. The science of heat, work, and the transformation between them. h. Everything that lies outside the system in thermodynamics. i. The heat transferred or lost to the system.Page 2 of 10 2. If 45.5g of NH3 and 90.3g of O2 produce 32.9g of H2O, find the percent yield? 4 NH3 + 3 O2  2 N2 + 6 H2O a. 21.6% b. 68.4% c. 45.6% d. 95.1% e. 64.7% 3. What is the oxidation number for carbon in C2O4-2 ? a. +2 b. 0 c. +4 d. +3 e. +6 4. Which of the following are precipitation reactions? X. Na3PO4(aq) + CrCl3(aq) Y. Fe(ClO3)2(aq) + NaOH(aq) Z. NH4NO3(aq) + Mg(CH3COO)2(aq) a. X and Y b. Y and Z c. Z only d. Y only e. X only 5. Which of the following lists two weak acids? a. CH3COOH and Ca(OH)2 b. H2CO3 and HClO4 c. H2SO4 and HNO3 d. CH3NH2 and NaOH e. HCN and C6H5COOHPage 3 of 10 6. What is the molarity of a 14.7% NaClO3 solution if the density of the solution is 1.09g/mL? a. 0.138 M b. 1.51 M c. 766 M d. 0.00138 M e. 0.00151 M 7. Which statements are false? X. Strong electrolytes are compounds that dissolve completely to form ions. Y. Strong acids are weak electrolytes. Z. Most molecular compounds are electrolytes. a. X and Y b. Z only c. X only d. X and Z e. Y and Z 8. What is the oxidation number for S in MgS2O3? a. +2 b. -2 c. -1 d. +1 e. 0 9. Which of the following involve(s) a weak acid with a strong base? X. HCN(aq) + NH3(aq) Y. HCOOH(aq) + NaOH(aq) Z. H2CO3(aq) + LiOH(aq) a. X and Z b. Y only c. Z only d. Y and Z e. X and YPage 4 of 10 10. Which of the following reactions requires additional energy to occur? X. Mg(s) + Li2S(s)  MgS(s) + 2 Li(s) Y. CaCO3(s) + 2 K(s)  K2CO3(s) + Ca(s) Z. 2 FeI3 (aq) + 3 F2(g)  2 FeF3(s) + 3 I2(s) a. X and Y b. Y and Z c. Z only d. Y only e. X only 11. Which statement best describes the reaction between rubidium hydroxide and hydrochloric acid? a. This is an exchange reaction. b. One of the products is a soluble ionic compound. c. This is an acid-base reaction. d. The net ionic equation for the reaction is H+(aq) + OH-(aq)  H2O(l) e. All of the above. 12. Which statements are true about the following reaction? Na2CO3(s) + HCl(aq)  NaO + CO2 + H2O X. This is a gas-forming reaction. Y. The CO2 comes from the rapid decomposition of H2CO3. Z. The reaction is already balanced. a. X and Y b. Y and Z c. X only d. Z only e. X and Y 13. What volume of 0.400M HCl(aq) do you need to dissolve 12.0g of solid calcium carbonate? a. 0.599 mL b. 599 mL c. 59 mL d. 50.99 mL e. 5.9 mLPage 5 of 10 14. Which reactants would give a product spontaneously? X. CoCl2(aq) + Br2(l) Y. NiSO4(aq) + Sr(s) Z. Ca(s) + Ba(NO3)2(aq) a. X and Z b. Y only c. Z only d. Y and Z e. X and Y 15. It takes 15mL of a 0.100M Ca(OH)2(aq) solution to titrate 25mL of a HNO3(aq) solution. What is the initial concentration of the HNO3(aq) solution? HNO3(aq) + Ca(OH)2(aq)  Ca(NO3)2(aq) + H2O(l) a. 0.120 M b. 0.060 M c. 0.333 M d. 0.167 M e. None of the above 16. Which statements are false? X. The equivalence point is reached when stoichiometric amounts of one substance have been added to another. Y. In titrations, the analyte is the substance of known concentration. Z. Indicators reveal when you reach the equivalence point in a titration. a. Y and Z b. Z only c. X only d. X and Z e. X and Y 17. In the reaction below, which statement is false? 2 KClO3(s)  2 KCl(s) + 3 O2(g) a. O is oxidized. b. Cl is reduced c. K is reducing agent d. This is a decomposition reaction. e. This is a redox reaction.Page 6 of 10 18. If the following reaction has a percent yield of 45.4% and you’re given 30.0 g of MgCO3 and 20.0g of HF, what is the actual yield of CO2? MgCO3 + 2 HF  MgF2 + CO2 + H2O a. 9.99 g b. 7.11 g c. 22.0 g d. 15.7 g e. 34.5 g 19. Which of the following will not produce a precipitate? a. Ca(ClO3)2 + H2SO4 b. Na2CO3 + AgNO3 c. NH4Cl + Ba(CH3COO)2 d. Li2C2O4 + CoSO4 e. Rb3PO4 + Cu(ClO4)2 20. What is the theoretical yield of PbCl2 from the reaction below given 14.8g of KCl and 51.2g of Pb(NO3)2? KCl + Pb(NO3)3 → KNO3 + PbCl2 a. 43.0 g b. 55.2 g c. 21.5 g d. 27.6 g e. 33.0 g 21. How much energy is necessary to raise the temperature of 47.8g of water by 91.0˚C? a. 18200 J b. 68.9 J c. 84.9 J d. 1010 J e. 2005 JPage 7 of 10 22. A reaction in a bomb calorimeter containing 800g of water causes the temperature of the bomb and water to rise by 26°C. The bomb has a heat capacity of 287 J/°C. What is the reaction’s ΔE in kj? a. -4590 kJ b. 4590 kJ c. -94.5 kJ d. 94.5 kJ e. 961 kJ 23. How much energy does it take to melt 15g of solid Au that is initially at 800°C? The m.p. of gold is 1064°C, specific heat capacity for Au(s) is 0.1290 J/g°C, and ΔHfusion for Au(s) is 63.70 J/g. a. -1466 J b. -510.8 J c. 1466 J d. 510.8 J e. -955.55 J 24. How many joules are required to heat a frozen can of juice (360 grams) from -5 0 C (the temperature of an overcooled refrigerator) to 110 0C (the highest practical temperature within a microwave oven)?Page 8 of 10 25. Balance the reaction below and use the table below to find the ΔHrxn: CO(g) + H2(g)  C2H5OH(g) + H2O(g) Compound ΔH°f (kJ/mol) CO(g) -110.5 CO2(g) -393.5 C2H5OH(g) -235.1 C2H5OH(l) -277.1 H2O(l) -285.8 H2O(g) -241.8 a. -366.4 kJ b. -255.9 kJ c. -299.9 kJ d. 366.4 kJ e. 255.9 kJ 26. Which statements are true? X. An endothermic process is one in which the system loses energy to the surroundings. Y. …