CHEMISTRY CP Name: Period: CHEMISTRY SPRING FINAL REVIEW SHEET NOTE: Below are concepts that we have covered in class throughout the second semester. Questions are organized by chapter/concept to help you study. You need to be able to understand the concepts listed AND apply this knowledge to answer the questions that are provided. I would highly suggest that you work the concepts and problems listed on this review sheet and also go over previous review sheets for each unit. In addition to a Periodic Table, Ion Chart, and Scientific Calculator, you may have one 4 x 6 card (BOTH SIDES) with any notes, formulas, or constants you may need. UNIT 5 STOICHIOMETRY Mole Conversions - Mole to mass (and vice versa) conversions - Mole to molecules (and vice versa) conversions - Molecules to mass (and vice versa) conversions Stoichiometry - Mole ratio - Molar mass - Mole to mole - Mole to mass and Mass to mole - Mass to mass Limiting reactants - Be able to show work to find limiting reactants, excess reactants, and product formed Percent Yield - Theoretical yield - Actual yield - Percent yield formula Percent composition Empirical formula Molecular formula DEFINITIONS AND PRACTICE PROBLEMS: Mole Concept 1. Know the definition of a mole. 2. Know Avogadro s Number. 3. Be able to calculate the molar mass for a compound. As an example: Calculate the molar masses of MgCO3 and HNO3. 4. Make the following conversions: a. What is the number of moles of CaS in 120 grams of the compound? b. What is the mass in grams of 18.06 10 23 molecules of CO2? c. How many molecules of CO2 are in.50 moles? Stoichiometry 5. Given the equation: Zn + HCl ZnCl2 + H2 a. How many moles of hydrogen will be formed when 4 moles of HCl are reacted? b. How many moles of Zn will be reacted to form 3 moles of ZnCl2? c. How many moles of HCl will be needed to react completely with 3 moles of Zn? 6. Given the equation: Na + H2O NaOH + H2 According to the following reaction, calculate the number of grams of sodium hydroxide that will be produced if 8.215 grams of sodium are reacted with excess water. 7. Given the equation: CO + O2 CO2 How many grams of carbon monoxide are required to produce a total of 44 grams of oxygen? Limiting Reactant 8. Given the equation: C6H12O6 + O2 CO2 + H2O If 35 grams of C6H12O6 react with 40 grams of O2, how many grams of CO2 will be produced? What is the limiting reactant? 9. Given the equation: Mg(s) + HCl(aq) MgCl2(aq) + H2(g) A 1.4 g sample of magnesium is treated with 8.1 g of hydrochloric acid to produce magnesium chloride and hydrogen gas. a. What is the limiting reactant? b. What is the excess reactant? c. How many grams of hydrogen are produced? Percent Yield 10. Given the equation: Mg + HNO3 Mg(NO3)2 + H2 a. If 40 grams of magnesium (Mg) are reacted with excess nitric acid (HNO3), how many grams of hydrogen are produced. b. If 1.7 grams of hydrogen was actually produced, what was the percent yield? (Hint: Use your answer from part a)
11. The amount of product in a given reaction turns out to be only 2.34 grams although the theoretical amount was calculated to be 3.12 grams. What is the percentage yield? 12. Given the balanced equation: NaHCO3 + HCl NaCl + H2O + CO2 In the reaction of 10 grams of NaHCO3 with excess HCl, 4.5 grams of NaCl is actually produced. What is the percentage yield from this reaction? Empirical and Molecular Formula 13. What is the empirical formula for fructose, C6H12O6? 14. Determine the empirical formula for succinic acid that is composed of 40.60% carbon, 5.18% hydrogen, and 54.22% oxygen. 15. A sample of a compound is composed of 12.8 grams of copper and 3.5 grams of chlorine. What is the empirical formula of the compound? 16. The empirical formula of a compound is CH2O and the molar mass is 150 g/mol. What is the molecular formula of the compound? UNIT 6 States of Matter, Kinetic Molecular Theory, Gas Laws States of matter - Particle arrangement - Particle motion Kinetic Molecular Theory Conversions - Pressure Units - Temperature Units - Absolute Zero Gas Laws - Graham s Law - Dalton s Law - Boyle s Law - Charles Law - Gay-Lussac s Law - Ideal Gas Law Volume Stoichiometry - Mole Conversions - Volume to Mole (vice versa) - Volume to Mass (vice versa) - Volume to Volume DEFINITIONS AND PRACTICE PROBLEMS: 17. Know the three common states of matter in terms of particle motion. 18. Be able to draw a picture of what the particles look like in each of the three states of matter. 19. What is plasma? Give two examples of where plasma is found? 20. What are the three assumptions of the Kinetic Theory? 21. What does STP stand for and what are its numerical values (i.e., give five for pressure and two for temperature)? 22. At what temperature does all molecular motion stop? What is the name for this temperature? 23. Convert the following temperatures from Celsius to Kelvin and Kelvin to Celsius: a. 22 C c. 220 K b. 474 C d. 390 K 24. Convert the following pressure units to the indicated pressure units: a. 2.6 atm = mmhg b. 120 mmhg = KPa Gas Law Constants R = 0.0821 L atm mol K R = 8.315 L kpa mol K R= 62.4 L mmhg mol K 25. There is a mixture of three gases in a closed container. Gas A exerts a pressure of 15 psi, Gas B a pressure of 6.5 psi, and the total pressure is 25.7 psi. What is the partial pressure of Gas C? 26. Which of the following gases would diffuse most rapidly: N2, O2, He, Cl2? 27. What is the ratio of the rate of diffusion of H2 to He? 28. A sample of gas occupies 200 cm 3 at STP. Calculate the volume this same amount of gas would occupy at pressure of.75 atm and a temperature of 10 C. 29. Know that at STP, one mole of any gas is equal to 22.4 L. a. Determine the volume, in liters, occupied by 0.030 moles of CO2 gas at STP. b. How many moles of argon atoms are present in 44.8 L of argon gas at STP? 30. Given the reaction at STP: N2 + H2 NH3 How many liters of H2 will be required to react with 56 grams of N2? 31. Given the reaction at STP: H2 + O2 H2O What is the total volume water vapor produced if 40 liters of hydrogen gas are consumed in the reaction above? 2
32. According to Boyle s Law, what type of relationship do pressure and volume have? 33. A gas sample occupies 450 cm 3 at STP. Calculate the volume this gas would occupy at a pressure of 45 KPa and a temperature of 30 C. 34. What pressure in atm is required to compress 1.0 L of gas at 760 mm Hg to a volume of 50.0 L? 35. A 200 ml sample of air at STP is heated at constant volume until its pressure increases to 1500 mm Hg. What is the new temperature of the sample? 36. What is the molecular mass of a gas if.150 L have a mass of 4.22 g at 100 C and 1.05 atm. 37. What is the density of a gas at STP that has a molar mass of 44.0 g/mol? 38. A large balloon sits at the surface of the sea. After being lowered under the surface the balloon has its temperature tripled and its pressure halved. What will happen to its volume? USE THE GRAPH BELOW TO ANSWER QUESTIONS 39-40. 39. What gas law is described by the graph? 40. According to the graph, what type of relationship do the variables volume and temperature have? UNIT 7 Reaction Rates, Equilibrium, and Thermochemistry Factors that Affect Reaction Rate - Concentration - Surface Area - Temperature - Catalyst Equilibrium - Le Chatelier s Principle - Equilibrium Constants (Keq) Potential Energy Diagrams - Potential Energy of Reactants/Products - Activation Energy - Heat of Reaction - Exothermic vs. Endothermic Phase Diagrams - Solid, Liquid, Gas - Triple Point - Critical Point Heating/Cooling Curves - Temperature Change - Phase Change - Hfusion and Hvaporization Specific Heat Calculations/Phase Change Calculations - Five Step Problems DEFINITIONS AND PRACTICE PROBLEMS: Rates of Reaction 41. Know what the rate of a chemical reaction can be measured by. 42. Know what factors affect the rate of a reaction and how they affect the rates of reaction. For example, what would happen to the rate of reaction if the following actions were performed? a. Removing an enzyme b. Decreasing temperature c. Increasing surface area d. Diluting a solution e. Adding heat f. Adding an enzyme g. Breaking a reactant into smaller pieces 43. Know what conditions are true of a chemical reaction at equilibrium. Le Chatelier s 44. What does Le Chatelier's Principle say? 45. What are three kinds of stresses that can be placed on a system? 46. Use the following reaction at equilibrium answer the questions: A(g) + 3 B(g) 2 C(g) + heat a. What direction will the reaction shift if heat is added? 3
b. What direction will the reaction shift if pressure is increased? c. What will happen to the concentration of A if the temperature decreases? d. What will happen to the concentration of C if more A is added? e. What direction will the reaction shift if more C is added? 47. Use the following reaction at equilibrium answer the questions: A(g) + B(aq) C(s) + heat ΔHrxn= -453 kj/mol a. The pressure of A in the reaction chamber is increased. b. The temperature of the reaction is increased by 20 0 C. c. A catalyst is added to the system. 48. At 1000 o C, container has an equilibrium mixture consisting of 0.102 mol/l of ammonia, 1.03 mol/l of nitrogen, and 1.62 mol/l of hydrogen. Calculate the Keq for the equilibrium system. N (g) + 3H (g) 2NH (g) 2 2 3 49. The equilibrium constant for the equilibrium reaction CO(g) + H2O(g) CO2(g) + H2(g) is 302 at 600K. What is the value of the equilibrium constant for the reverse reaction at the same temperature? POTENTIAL ENERGY DIAGRAMS Use the potential energy diagram to the left to answer the following questions? 50. Which curve (A or B) represents the catalyzed reaction? 51. According to the diagram above, is the forward chemical reaction endothermic or exothermic? Use the potential energy diagram to the right to answer the following questions. 52. Is the forward reaction endothermic or exothermic? 53. Which letter represents the activation energy? 54. Which letter represents the potential energy of the products? 55. Which letter represents the heat of reaction? 56. Which letter represents the activation energy of the reverse reaction? PHASE DIAGRAMS USE THE DIAGRAM TO THE LEFT FOR QUESTIONS 57-60. 57. According to the diagram, at which point are the solid, liquid and gas phases in equilibrium (exist at the same temperature and pressure)? 58. What is this point called? 59. Which temperature and pressure correspond to the critical point? 60. At a constant pressure of 60 atm, which phase change occurs from 250 K to 200 K? 4
HEATING/COOLING CURVES 61. Use the diagram below: B C E Label the solid, liquid and gas phases on the diagram to the left. (A) Which of the letters on the diagram correspond to the liquid phase only? (B) Which of the following letter(s) correspond to when a phase change is occurring? (C) Could this substance be water based on the melting point/boiling point of water? D A ENERGY CALCULATIONS Equation 1: Calculating Heat Equation 2: Calculating ΔHfus Equation 3: Calculating ΔHvap Q = mass T Cp Q = ΔHfus mass Q = ΔHvap mass Constants: Heat of fusion = 334 J/g Heat of vaporization = 2260 J/g Specific heat for solid water (ice) = 2.06 J/g C Specific heat for liquid water = 4.18 J/g C Specific heat for gaseous water (steam) = 2.02 J/g C Boiling point of water = 100 C Freezing point of water = 0 C 62. How many joules of heat energy are absorbed when 200.0 grams of water are heated from 10.0 C to 40.0 C? 63. What is the total amount of heat energy released when 125 grams of water is cooled from 50.0 C to 25 C 64. How much energy is needed to heat 87g of ice at -10 C to water vapor at 120C? 65. The boiling point of ethanol is 78 C. How much heat is required to heat 100 grams of ethanol from 25 C to its boiling point and then to turn it into a vapor? Cp = 2.44 J/g C Hvap = 855 J/ UNIT 8 Solutions, Solubility, Units of Concentration, Acids & Bases Properties of water - Bonds: Covalent and Hydrogen - Polarity (universal solvent) - Surface tension - Capillarity (Capillary action) - Low Vapor Pressure - Density Parts of a solution - Solute - Solvent Units of concentration - Molarity - Molality - Mole Fraction - Percent by Mass - PPM - G/L Factors that Affect Solubility - Temperature - Pressure Colligative Properties - Freezing point depression - Boiling Point Elevation Properties of Acids and Bases - Arrhenius Definition - Bronsted- Lowry Definition - Conjugate Acids/Base Pairs - ph and poh 66. What gives water its unique properties such as lower density in solid state, low vapor pressure, high specific heat, and high surface tension? 67. What causes high surface tension in water? 68. Why is water considered the universal solvent? 69. Know the definition of a solution, solute and solvent. Given an example of a solution. 70. Give an example of a solid, liquid, and gas solution. Identify the solute and solvent. 71. What happens to ionic compounds such as NaCl when they dissolve in water? 72. Why does a covalent compound like sugar (C12H24O12), dissolve in water? 5
73. What is the difference between unsaturated, saturated and supersaturated solutions? 74. A glass of water has 10g of sugar dissolved in it. If more sugar can be added to dissolve in the water, is the solution unsaturated, saturated, or supersaturated? UNITS OF CONCENTRATION 75. If 8.7 g of Na2CO3 is dissolved in 800 ml of water, what is the molarity of the solution? What is the answer in PPM?(1 ml of water = 1 g of water) 76. How many grams of beryllium chloride, BeCl2, are needed to make 125 ml of a 0.050 M solution? 77. How many grams of MgCl2 would be needed to make 1.5 L of a 0.40 M solution? 78. Suppose you had 7.00 moles of solute dissolved into 5.80 L of solvent. What's the molality? (1 L = 1 kg) 79. If I make a solution by adding 83 grams of sodium hydroxide, NaOH, (solute) to 750 ml of water (solvent) a. What is the molality of sodium hydroxide in this solution? b. What is the percent by mass of sodium hydroxide in this solution? c. What is the mole fraction of sodium hydroxide in this solution? 80. If I make a solution by adding water to 35 ml of methanol (CH3OH) until the final volume of the solution is 275 ml, what is the percent by volume of methanol? SOLUBILITY 81. Know how temperature affects the solubility of a solid, liquid and gas. Be able to identify how a solubility of a solid, liquid and gas would plot on a curve. 82. Using the solubility graph below, determine if the following solutions are saturated, unsaturated or supersaturated. If they are anything but saturated, list two things you can do to make them saturated (include numbers). Solution (in 100 mg water) Saturated, Unsaturated, Supersaturated +/- how many C to make saturated +/- how many grams to make saturated 10 g of KClO3 at 30 C 30 g of NaCl at 40 C ACIDS AND BASES 83. What are the properties of acids and bases? 84. What is an Arrhenius acid and base? How is it different from a Bronsted Lowry acid and base? 85. Identify the acid, the base, the conjugate acid and the conjugate base in the reaction: NH3 (g) + HOH (l) NH4 + (aq) + OH - (aq) 86. Identify the acid, the base, the conjugate acid and the conjugate base in the reaction: HCO3 - (aq) + HOH (l) CO3 2- (aq) + H3O + (aq) 87. If given the hydrogen ion concentration, be able to determine the ph of an aqueous solution. As an example: What is the ph of an aqueous solution with a hydrogen ion concentration of 1 10-4? 88. If the hydroxide ion concentration is 1 10-12, what is the ph of the solution? 89. If the ph is 2.37, what is the [H + ]? 90. If the ph is 11.36, what is the concentration of hydroxide ions? 91. Given the reaction: NH3 + H2O NH4 + + OH - Be able to identify which reactant acted as an acid and why. Remember: H + is a proton. 92. What are the products of a neutralization reaction? Predict the products of the following reactions: a. HCl + Mg(OH)2 b. H2CO3 + KOH 6