2. Draw and label an exothermic chemical reaction graph as it progresses. Draw and label an endothermic reaction progress diagram.

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1 Name: Block: Date: Honors Chemistry Spring Final Review 1. Calculate the specific heat of cobalt if a 31 g sample at an initial temperature of 25 C has 105 J of energy added to it. The final temperature was C J/g C 2. Draw and label an exothermic chemical reaction graph as it progresses. Draw and label an endothermic reaction progress diagram. 3. A 74 g cube of iron at 180 C is dropped into 36 g of water at 24 C. The specific heat of iron is 0.42 J/g C. Calculate the final temperature of the water and the final temperature of the metal C 4. Given: ClO(g) + O3(g) Cl(g) + 2O2(g) ΔH = -29.9kJ 2O3(g) 3O2(g) ΔH = 24.18kJ Calculate the change in enthalpy for Cl(g) + O3(g) ClO(g) + O2(g) kj 5. Calculate the final temperature of a system that has a 31 g sample of gold that has an initial temperature of 106 C. The 18 g sample of water in the calorimeter had an initial temperature of 24 C. The specific heat of gold is 0.32 J/g C C 6. In a very exothermic reaction a 60 g sample of cesium is dropped into 30 g water. The cesium was originally at 25 C. The final temperature reached 219 C. The specific heat of cesium is 0.24 J/g C. Calculate the initial temperature of the water C 7. What is the change in enthalpy when 11.8 g of iron reacts with excess O2 to form magnetite, according to the equation 3Fe + 2O2 Fe3O4 H o = kJ? Is the reaction endothermic or exothermic? kj 8. Find ΔH for the reaction 2H2(g) + 2C(s) + O2(g) C2H5OH(l), using the following thermochemical data. C 2 H 5 OH(l) + 2O 2 (g) 2CO 2 (g) + 2H 2 O(l) ΔH = 875 kj C(s) + O 2 (g) CO 2 (g) ΔH = kj H 2 (g) + ½O 2 (g) H 2 O(l) ΔH = kj kj 9. Calculate ΔH for the reaction 4NH3(g) + 5O2(g) 4NO(g) + 6H2O(g), f rom the following data. N 2 (g) + O 2 (g) 2NO(g) ΔH = kj N 2 (g) + 3H 2 (g) 2NH 3 (g) ΔH = 91.8 kj 2H 2 (g) + O 2 (g) 2H 2 O(g) ΔH = kj kj

2 10. Identify the following reactions that you would expect to be spontaneous at relatively high temperatures? Identify the reactions that you would expect to be spontaneous at relatively low temperatures. ΔH ΔS Spontaneous a. Energy +2NH3(g) N2(g) + H2(g) + + High temps b. 2NO2(g) N2O4(g) + energy - - Low temps c. Energy +CaCO3(g) CaO(s) + CO2(g) + - Never 11. Predict the sign of H, S, and G ΔH ΔS ΔG a. The reaction is always spontaneous b. The reaction is never spontaneous c. The reaction is spontaneous at low temperatures only d. The reaction is spontaneous at high temperatures only Use the thermodynamic data to calculate H, S, G for the following reactions at 25 C (298 K). Hf S a. CH4(g) + 2O2(g) CO2(g) + 2H2O(g) Substance (J/K mol) ΔH = kj/mol CH4(g) ΔS = -4 J/K mol CO2(g) ΔG = kj/mol C6H12O6(s) b. 6CO2(g) + 6H2O(l) C6H12O6(s) + 6O2(g) H2O(g) ΔH = 2802 kj/mol H2O(l) ΔS = -262 J/K mol O2(g) ΔG = kj/mol 13. Calculate G for each process and state whether the process is spontaneous or nonspontaneous. a. H= 145 kj,t = 293 K, S = 195 J/K kj/mol b. H= -232 kj, T = 273 K, S = 138 J/K kj/mol c. H= kj, T = 246 K, S = 100 J/K kj/mol 14. The mass of a Twinkie is 36.4 g which is 135 Calories. In the lab, a Twinkie is burned under a pop can calorimeter that has 98.7 ml of water in it. The initial temperature of the water was 24.6 C. After burning the Twinkie, 12.3 g is left and the final temperature of the water was 29.6 C. What is the percent error for this lab? 99.4% 15. When 1 mole of glucose (C6H12O6) is burned by your body, 2800 kj of energy is released. Calculate the change of enthalpy when 65 grams of glucose is burned kj 16. Determine if the following are endothermic or exothermic: a. A substance going from the gas to liquid phase exothermic b. A substance going from the solid to gas phase endothermic c. A negative enthalpy exothermic d. Metal releasing heat to water exothermic e. When there is more PE in the products than the reactants endothermic

3 17. Determine the amount needed for the following situations. All has to do with pure water. a. Melting 40 g of -14 C ice to 60 C Useful information: 24,572 J ΔH fus =.334 kj/g C ice = 2.09 J/g C b. Cooling 3.4 L of 113 C steam to 80 C -6,472.4 J c. Cooling 56 ml of 95 C water to 32 C -14,761.2 J d. Heating 50 grams of -35 C ice to 120 C 141,337.5 J ΔH vap = 2.26 kj/g Density = 1 g/ml C water = 4.18 J/g C C steam = 2.09 J/g C 18. List all the elements that have to be diatomic when they are by themselves in a reaction. N 2 O 2 F 2 Cl 2 Br 2 I 2 H Calculate the amount of strontium hydroxide formed from the reaction between 45 g strontium bromide and 56 g ammonium hydroxide g Sr(OH) How many moles of C6H14 are needed to react with 9.8 x 10 7 g oxygen? mol C 6 H Ammonium nitrate decomposes to yield nitrogen gas, water, and oxygen gas in the following reaction: 2NH4NO3 2N2 + O2 + 4H2O a. How many moles of nitrogen gas are produced when 36.0 g of NH4NO3 reacts? 0.45 mol N 2 b. If 7.35 mol of H2O are produced in this reaction, what mass of NH4NO3 reacted? 1176 g NH 4 NO Aluminum chips are sometimes added to sodium hydroxide based drain cleaners because they react to generate hydrogen gas which bubbles and helps loosen material in the drain by the following equation: 2Al(s) + 2NaOH(aq) + 2H2O(l) 2NaAlO2(aq) + 3H2(g) a. Balance the equation b. How many moles of H2 can be generated from 0.57 mol Al and 0.37 mol NaOH in excess water? 0.56 mol H Air is composed of 21% oxygen, 78% nitrogen, and 2% other gases. If 65 grams oxygen react with 68 grams nitrogen to form nitrogen monoxide and ozone (O3), how many liters of nitrogen monoxide are formed? (22.4 L = 1 mol) 22.8 L NO 24. A compound has the following percentages by mass; barium 58.84%, sulfur 13.74%, and the rest is oxygen. The molar mass is g/mol. What is the correct chemical compound? BaSO 4 For the next 5 questions, classify the following reactions as one or more of the following: Double Replacement Single Replacement Combustion Synthesis Decomposition Redox Acid/Base 25. HBr(aq) + RbOH(aq) H2O(l) + RbBr(aq) Double Replacement, Acid/Base

4 26. 3NbO2(aq) + 4Ag3N(g) 6Ag2O(s) + Nb3N4(g) Double Replacement 27. NaCl(s) + F2(g) NaF(g) + Cl2(g) Single Replacement, Redox 28. Sr(s) + O2(g) SrO(g) Synthesis, Redox 29. 2C10H22(g) + 31O2(g) 20CO2(g) + 22H2O(l) Combustion 30. Barium nitrate reacts with sodium carbonate to produce barium carbonate and sodium nitrate. Write the net ionic reaction for the equation. Ba 2+ (aq) + CO 3 2- (aq) BaCO 3 (s) 31. When designing an experiment, Elizabeth is trying to produce copper (I) oxide. The reaction requires copper metal and oxygen gas. Elizabeth uses a 400 ml beaker, weighing 82.5 g. She adds copper to the beaker and the final mass was g. She adds 38 g of oxygen gas and covers the beaker with a watch glass. What mass of copper (I) oxide could she produce? If her percent yield was 73%, what mass of copper (I) oxide did she produce? Could produce 29.4 g Cu 2 O Did produce 21.5 g Cu 2 O 32. A 200 g sample of magnesium sulfate that is 82% pure produces magnesium nitride in a 3:1 molar ratio when reacted with excess lithium nitride. What is the mass of magnesium nitride produced? 45.8 g Mg 3 N If g BaCl2 nh2o yields g of anhydrous BaSO4 after treatment with sulfuric acid, calculate n. (Did not teach you how to solve this sorry, thought I removed it before) 34. A certain carbohydrate compound (containing only C, H and 0) is 40.0% C, 6.72% H, and 53.3% O by mass. The experimentally determined molecular mass is 180 g/mol. What is the empirical and molecular formula for this carbohydrate? Empirical CH 2 O Molecular C 6 H 12 O A 5.00 g sample of hydrated barium chloride, BaCl2 nh2o, is heated to drive off the water. After heating, 4.26 g of anhydrous barium chloride, BaCl2, remains. What is the value of n in the hydrate's formula? BaCl 2 2H 2 O 36. A g sample of a hydrate of magnesium carbonate was heated, without decomposing the carbonate, to drive off the water. The mass was reduced to 7.58 g. What is the formula of the hydrate? MgCO 3 5H 2 O 37. Determine the oxidation number of the boldface element in these compounds/ions. a. HNO3 +5 c. B4O e. Ca3N2-3 b. Hg2 0 d. NH f. CuWO4 (Cu is +2) +6

5 38. Write the balanced molecular and net ionic of the following equations, include phase states: a. Na2CO3(aq) + Mg(OH)2(aq) Na 2 CO 3 (aq) + Mg(OH) 2 2NaOH(aq) + MgCO 3 (s) Mg 2+ (aq) + CO 3 2- (aq) MgCO 3 (s) b. NaClO3(aq) + Ca3(PO4)2(aq) 6NaClO 3 (aq) + Ca 3 (PO 4 ) 2 (aq) 2Na 3 PO 4 (aq) + 3Ca(ClO 3 ) 2 (s) Ca 2+ (aq) + 2ClO 3 - (aq) Ca(ClO 3 ) 2 (s) c. Hydrochloric acid reacts with sodium hydroxide HCl(aq) + NaOH(aq) H 2 O(l) + NaCl(aq) H + (aq) + OH - (aq) H 2 O(l) d. Silver nitrate reacts with iron (II) phosphate 6AgNO 3 (aq) + Fe 3 (PO 4 ) 2 (s) 2Ag 3 PO 4 (s) + 3Fe(NO 3 ) 2 (aq) 6Ag + (aq) + Fe 3 (PO 4 ) 2 (s) 2Ag 3 PO 4 (s) + 3Fe 2+ (aq) 39. Titanium (IV) oxide is a white substance produced by the action of sulfuric acid on the mineral ilmenite (FeTiO3): FeTiO3 + H2SO4 TiO2 + FeSO4 + H2O Its opaque and nontoxic properties make it suitable as a pigment in plastics and paints. In one process, 8.0 g of FeTiO3 yields 3.67 g of TiO2. What is the percent yield of the reaction? 87.1% yield 40. Are you glad you made it to the last questions for your last review for chemistry? Have a great summer!

6 Compound Standard Enthalpy of Formation* for Various Compounds Compound Compound Compound Ag 2 O(s) 30.6 C 2 H 5 OH(l) HCl(g) 92.3 NH 4 Cl(s) Ag 2 S(s) 31.8 C 2 H 6 (g) 84.7 HF(g) NH 4 NO 3 (s) AgBr(s) 99.5 C 3 H 8 (g) HgO(s) 90.7 NiO(s) AgCl(s) n-c 4 H 10 (g) HgS(s) 58.2 NO(g) AgI(s) 62.4 n-c 5 H 12 (l) HI(g) NO 2 (g) Al 2 O 3 (s) CO(g) HNO 3 (l) O 2 (g) 0 BaCl 2 (s) CO 2 (g) KBr(s) Pb 3 O 4 (s) BaCO 3 (s) CoO(s) KCl(s) PbBr 2 (s) BaO(s) Cr 2 O 3 (s) KClO 3 (s) PbCl 2 (s) BaSO 4 (s) Cu 2 O(s) KF(s) PbO(s) Ca(s) 0 CuO(s) Mg(OH) 2 (s) PbO 2 (s) Ca(OH) 2 (s) CuS(s) 48.5 MgCl 2 (s) PCl 3 (g) CaCl 2 (s) CuSO 4 (s) MgCO 3 (s) 1113 PCl 5 (g) CaCO 3 (s) Fe 2 O 3 (s) MgO(s) SiO 2 (s) CaO(s) Fe 3 O 4 (s) MgSO 4 (s) SnCl 2 (s) CaSO 4 (s) H 2 (g) 0 MnO(s) SnCl 4 (l) CCl 4 (l) H 2 O(g) MnO 2 (s) SnO(s) CH 3 OH(l) H 2 O(l) N 2 0 SnO 2 (s) CH 4 (g) 74.8 H 2 O 2 (l) NaCl(s) SO 2 (g) CHCl 3 (l) H 2 S(g) 20.1 NaF(s) SO 3 (g) C 2 H 2 (g) H 2 SO 4 (l) NaOH(s) ZnO(s) C 2 H 4 (g) HBr(g) 36.2 NH 3 (g) 46.2 ZnS(s) * All standard enthalpy values are at 25 C and 1 atmosphere of pressure. Σn S products Σ S reactants C = K

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