HEATING CURVE OF UNKNOWN SUBSTANCE

TEMPERATURE ( C) SPRING 218 FINAL EXAM REVIEW STUDY GUIDE GENERAL CHEMISTRY 55 MULTIPLE CHOICE QUESTIONS STUDENTS CAN USE A CALCULATOR & TEACHER PROVIDED PERIODIC TABLE UNIT 3: THERMOCHEMISTRY VOCABULARY & CONCEPTS 1. Boiling point- 2. Melting point- 3. Solid- 4. Liquid- 5. Gas 6. Kinetic energy 7. Potential energy 8. Endothermic 9. Exothermic- 1. Law of conservation of energy - 11. Temperature 12. Heat- 13. Heat of reaction (ΔH) 14. Calorimeter 15. Insulator 16. Conductor 17. POTENTIAL ENERGY DIAGRAM STUDENTS SHOULD BE ABLE TO ANALYZE & INTERPRET HEATING CURVE GRAPHS -Label the 3 phases, label the melting point and boiling point -Identifying changes or constants in kinetic energy or potential energy -Define and identify exothermic and endothermic changes and relate to heating curve HEATING CURVE OF UNKNOWN SUBSTANCE 6 5 4 3 2 1-1 5 1 15 2 TIME (minutes) 1

STUDENTS SHOULD BE ABLE TO USE THE SPECIFIC HEAT EQUATION Q = mcδt -to solve for any variable - use specific heat to identify unknown metal -relate specific heat to temperature change and conductive properties VARIABLE MEASUREMENT UNIT q QUANTITY OF HEAT ENERGY Joules J M mass Grams g C Specific heat J/g C capacity (constant) ΔT Tf - Ti C Change in temperature T i Initial C temperature T f Final temperature C SPECIFIC HEAT WATER 4.18 J /(g C) SAND.8 J/(g C) IRON.46 J/(g C) SILVER.24 J/(g C) BERYLLIUM 1.83 J/(g C) COPPER.38 J/(g C) COBALT.42 J/(g C) MAGNESIUM 1. J/(g C) NICKEL.5 J/(g C) substance specific heat Rate of Temperature changes water 4.18 HIGH slow Conductor Insulator NICKEL LOW.5 FAST X STYROFOAM HIGH SLOW X STUDENTS SHOULD BE ABLE TO EXPLAIN HOW TEMPERATURE IS DIFFERENT THEN HEAT. TERM DEFINE EXAMPLE TEMPERATURE The average kinetic energy, or 55 C movement of particles HEAT Heat flows from a warm object to a cooler object Holding a heat pack to warm your hands. 2

PRACTICE TEST QUESTIONS 18. What is the melting point of SUBSTANCE X? -2 C 19. What is the boiling point of SUBSTANCE X? 15 C 2. What phase of matter is the region labeled A? SOLID 21. What phase of matter is the region labeled E? GAS 22. Which regions of the graph does both a solid and liquid exist simultaneously? B 23. Which region of the graph is potential energy changing? B AND D 24. Identify as an endothermic or exothermic change? a. solid melting into a liquid ENDOTHERMIC b. gas condensing into a liquid ENDOTHERMIC c. liquid solidifying into a solid EXOTHERMIC 25. Which of the substances would change temperature quickly? METALS such as silver and copper 26. What kind of substances are best to construct a calorimeter? Styrofoam, doesn t change temperature easily SUBSTANCE SPECIFIC HEAT WATER 4.18 J /(g C) SAND.8 J/(g C) IRON.46 J/(g C) SILVER.24 J/(g C) BERYLLIUM 1.83 J/(g C) COPPER.38 J/(g C) COBALT.42 J/(g C) MAGNESIUM 1. J/(g C) NICKEL.5 J/(g C) 27. Calculate the quantity of heat needed to heat a 1.66 gram sample magnesium from 32 C to 85? Q = mcδt (1.66 g) (1. J/g C)85-32 = 564.98 J 28. Calculate the change in temperature of a 5. gram sample that loses 18 Joules of heat energy? Q = mcδt -18 J = (5 g)(4.18 J/g C) ΔT ΔT = -86 C 3

29. A 25 gram substance changes temperature from 15 C to 55 C. Identify the substance that absorbs 24 Joules of heat energy? Q = mcδt 24 J = (25 g)c (55 C 15 C) specific heat =.24 = silver 3. Identify the graph as exothermic or endothermic? 31. Would the graph have a + ΔH or ΔH? UNIT 4: REACTION RATES AND EQUILIBIRIUM VOCABULARY & CONCEPTS 32. solvent 33. Solute- 34. Concentration 35. Molarity 36. Molality 37. Freezing point depression 38. Boiling point elevation - 39. Saturated 4. Unsaturated - 41. Supersaturated - 42. Catalyst 43. Activation energy 44. Equilibrium 45. Temperature 46. Pressure 47. LeChatelier s principle STUDENTS SHOULD BE ABLE TO CALCULATE MOLARITY AND MOLALITY STUDENTS SHOULD BE ABLE TO CALCULATE FREEZING POINT DEPRESSION & BOILING POINT ELEVATION STUDENTS SHULD BE ABLE TO INTERPRET SOLUBILITY CURVES STUDENTS SHOULD BE ABLE TO DESCRIBE HOW A CATALYST AFFECTS A CHEMICAL REACTION STUDENTS SHOULD KNOW THE CHARACTERISTICS OF ENDOTHERMIC AND ENDOTHERMIC REACTIONS STUDENTS SHOULD BE ABLE TO CONVERT BETWEEN ENERGY & MASS USING BALANCED EQUATIONS STUDENTS SHOULD BE ABLE TO APPLY LECHATELIER S PRINCIPLE TO CHANGES MADE TO A CHEMICAL REACTION AT EQULIBRIUM EXOTHERMIC DEFINE ΔH EXAMPLE REACTIONS POTENTIAL ENERGY DIAGRAM ENDOTHERMIC 4

PRACTICE TEST QUESTIONS 48. What mass of KNO 3 will dissolve at 62 C? 15 grams 49. At what temperature will 8 grams of KCLO 3 dissolve? 2 C 5. Which compound dissolves the least at 4 C? Ce 2(SO 4) 3 51. How much NH 3 would saturate 1g of H 2O at 2 C? 52 grams NH 3 52. 115 g NaNO 3 dissolves in 1g of H 2O at 4 C, is this solution super saturated or unsaturated? SUPERSATURATED 53. What is the molarity of a solution containing 8.6 moles NaCl dissolved in 2.6 L of H 2O? M = moles = 8.6 mol NaCl = 3.3 M Liter 2.6 L 54. What is the molality of a solution containing 6.88 moles C 6H 12O 6 per 1.2 kg of solvent. m = moles = 6.88 moles = 5.73m Kg 1.2 kg 55. A copper chloride solution is made from dissolving 75.66 grams CuCl 2 into.19 L of water. What is the molarity of the solution? 75.66 g CuCl 2 x 1 mole CuCl 2 =.56 mole 134 g CuCl 2 M = moles =.56 moles = 2.97M Solvent K f C/m K b C/m f.p. C b.p. C Liter.19 L 56. Calculate the freezing point of 112 g glucose In 25 g of water. ΔT = k fm f.p. ΔT = new F.P. 112 g C 6H 12O 6 x 1 mole C 6H 12O 6 =.62 mole C 6H 12O 6 18g C 6H 12O 6 ΔT = 1.86 (.62 mole/.25kg) = 4.63 C - 4.63 C = -4.63 C Water 1.86.512 1 Acetic 3.9 3.7 16.6 117.9 acid 57. What is the boiling point of a solution made from dissolving 26 grams C 6H 12O 6 into 1.2 kg of acetic acid. ΔT = k bm b.p. + ΔT = new B.P. 26 g C 6H 12O 6 x 1 mole C 6H 12O 6 =1.44 mole C 6H 12O 6 18g C 6H 12O 6 ΔT = 3.7 ( 1.44 mole/1.2 kg) = 3.684 C 117.9 + 3.684 C = 121.584 C 5

Label as true/false 58. Endothermic reactions absorb energy? TRUE 59. A catalyst will lower the activation energy of a chemical reaction. TRUE 6. The ΔH of exothermic reactions is positive. FALSE 61. A catalyst will cause a chemical reaction rate to increase. TRUE 62. Energy flows from a substance of high temperature to low temperature. TRUE 63. What is the ΔH of this reaction? Ca(OH) 2 (s) + CO 2(g) H 2O (g) + CaCO 3 (s) + 69.1 kj 64. -69.1 kj 65. Consider the reaction: C 6H 12O 6 + 6 O 2 6 CO 2 + 6 H 2O ΔH = -288 KJ What mass of oxygen will be used to produce 3 KJ of energy? -3 KJ x 6 moleso 2 x 32 grams O 2 = 25.13 grams O 2-288 KJ 1 moles O 2 66. Consider the reaction: HCN (g) + 2 H 2(g) CH 3NH 2(g) ΔH = -138 kj/mole What amount of energy is released when 25 grams of H 2 is consumed? 25 g H 2 x 1 moles H 2 x -138 KJ = -862.5 KJ H 2 2 g H 2 2 moles H 2 67. Consider the reaction 2 C 2H 6 (g) + 7 O 2 (g) 4 CO 2 (g) + 6 H 2O (g) H = -88 KJ/mole If 54.66 grams of oxygen gas was reacted, how much energy will be released to the surroundings? 54.66 grams O 2 x 1 moleso 2 x -88 kj = - 197.17 grams O 2 32 g O 2 7 moles O 2 68. Given the following reaction at equilibrium: 12.6 kcal + H 2(g) +I 2(g) 2 HI(g) Which way will the equilibrium shift when the following changes are made? a) Increasing temperature SHIFT RIGHT e) increasing H 2 concentration SHIFT RIGHT b) Decreasing temperature SHIFT LEFT f) increasing I 2 concentration SHIFT RIGHT c) Increasing pressure NO CHANGE g) increasing HI concentration SHIFT LEFT d) Decreasing pressure NO CHANGE h) decreasing HI concentration SHIFT RIGHT 69. Consider the following reaction: N 2(g) + 3 H 2(g) 2NH 3(g) + 22. kcal What changes will increase the amount of NH 3 made? DECREASING NH 3 CONCENTRATION INCREASE PRESSURE INCREASING N 2 CONCENTRATION DECREASE TEMPERATURE INCREASING H 3 CONCENTRATION UNIT 5: NUCLEAR CHEMISTRY VOCABULARY & CONCEPTS 7. Alpha 71. Beta 72. Gamma 6

73. Half life 74. Radioactivity 75. Fission- 76. Fusion 77. Transmutation 78. Solar radiation 79. Electromagnetic spectrum 8. Wavelength 81. White dwarf 82. Super giant- 83. Red giant - 84. Supernova 85. Black hole 86. Big bang theory - 87. Telescope STUDENTS SHOULD BE ABLE TO COMPARE/CONTRAST NUCLEAR CHANGE, CHEMICAL CHANGE, AND PHYSICAL CHANGE Type of change DESCRIPTION EXAMPLE REACTION TEMPERATURE CHANGES Nuclear change Changes to nucleus 226 88 Ra 4 222 He + 2 86 Rn 1 million C Chemical change Changes to electrons, CO2 + H2O C6H 12O6 + O2 2, C same elements on reactant & product side of equation Physical change Phase change H 2O (s) H 2O(l) Ice melting into water 1 C 241 STUDENTS SHOULD BE ABLE TO INTERPRET PROPER NUCLEAR NOTATION 95 Am STUDENTS SHOULD BE ABLE TO IDENTIFY RADIOACTIVE ELEMENTS Above which atomic number are all elements radioactive? 82 STUDENTS SHOULD BE ABLE TO BALANCE A NUCLEAR EQUATION INCLUDING IDENTIFYING THE MISSING COMPONENT STUDENTS SHOULD BE ABLE TO COMPARE/CONTRAST FISSION AND FUSION Type of nuclear change DEFINE SAMPLE REACTION USED FOR? FISSION Fission is division! split Nuclear power plants and weapons FUSION Combine or join 4 1 1 H 4 2 He + 2 +1 e Sun & other stars STUDENTS SHOULD BE ABLE TO COMPARE/CONTRAST THE TYPES OF READIOACTIVITY:ALPHA, BETA, GAMMA 7

TYPE OF RADIOACTVE DECAY ALPHA BETA SYMBOL size Can be stopped by? (penetrative power) 4 2 He or α 4 largest 1 e or β middle Skin, clothes, wood, metal foil, concrete, lead wood, metal foil, concrete, lead EXAMPLE REACTION 235 92 U 14 6 C 4 231 He + 2 9 Th 14 e + 1 7 N GAMMA pure γ or γ energy smallest Thick concrete, lead 4 19 K + 4 e γ + 1 18 Ar STUDENTS SHOULD BE ABLE TO PERFORM HALF LIFE CALCULATIONS STUDENTS SHOULD BE ABLE TO DESCRIBE THE BIG BANG THEORY STUDENTS SHOULD BE ABLE TO DESCRIBE THE NUCLEAR PROCESSES OCCURING IN THE SUN AND HOW SOLAR RADIATION AFFECTS EARTH. STUDENTS SHOULD BE ABLE TO DESCRIBE THE ELECTROMAGNETIC SPECTRUM AND WHAT ITS USED FOR STUDENTS SHOULD BE ABLE TO LIST THE STAGES IN THE STAR CYCLE AND RELATE TO OUR SUN PRACTICE TEST QUESTIONS Label the following statements as properties of: NUCLEAR CHANGE, CHEMICAL CHANGE, OR PHYSICAL CHANGE 88. Temperature change of 1, C CHEMICAL CHANGE 89. A new element is formed NUCLEAR CHANGE 9. Same substance on reactant and product side of equation, just a different phase of matter PHYSICAL 91. Temperature change of 1 C PHYSICAL CHANGE 238 92. Label the atomic number and the atomic mass for: 92 U atomic number atomic mass 93. Balance the following nuclear reactions be writing in the missing component. a. 2 1 H + 3 1 H 4 2 He + 1 1 n b. 241 95 Am + 4 243 He 2 93 Np + 2 1 n 8

c. 187 75 Re + 2 1 H 188 75 Re + 1 1 H d. 1 5 B + 4 2 He 13 7 N + 1 1 n 94. Which of the following isotopes are radioactive? (circle all that apply) Cl U Ra Sm Sb Bk 95. Rank alpha, beta, gamma by increasing size? Gamma, beta, alpha 96. Rank alpha, beta, gamma by decreasing penetrative power? gamma, beta, alpha 97. Identify as alpha, beta, or gamma decay. a) 226 88 Ra 4 2 He + 222 Rn ALPHA DECAY 86 b) 37 18 Ar + 1 e γ + 37 Cl GAMMA DECAY 17 c) 238 92 U 234 9 U + 4 He ALPHA DECAY 2 d) 234 91 Pa 234 e + U BETA DECAY 1 92 98. Identify as fission or fusion a) 235 139 94 U + n Ba + 92 56 36 Kr + 3 1 n FISSION b) 1 1 H + 1 1 H + 1 1 H + 1 1 H 4 2 He + 2 e FUSION +1 c) 3 1 H + 2 1 H 4 2 He + 11 n FUSION d) 235 92 9 143 U + n Sr + 38 54 Xe + 3 1 n FISSION e) FISSION f) FUSION 9

99. The half life of Ra-22 is 4 days. How much of a 125 gram sample remains after 12 days? 12 days = 3 125 (.5) 3 = 15.625 grams 4 days 125 (.5)(.5)(.5) = 15.625 grams remaining 1. How much of a 1 gram sample of 198 Au is left after 13.5days. The half life if Au-198 is 2.7 days. 13.6 days = 5 1 (.5) 5 = 3.125 grams remaining 2.7 days 1 (.5) )(.5)(.5) (.5)(.5) = 3.125 grams remaining 11. What is the half life of K-42 if 16.8 grams of a 268.8 gram sample are remaining after 49.6 hours? 268.8/2 =134.4 4 half lives occurred 49.6 hours = 4 134.4/2 =67.2 h 67.2/2 =33.6 33.6/2 =16.8 half life of K-42 is 12.4 hours 12. List two effects of solar radiation? source of vitamin D, sun burn, source of energy for our planet, source of energy for photosynthesis 13. How are the dark lines of the spectrum different then the colored lines? dark lines show wavelengths of energy that are absorbed, colorful lines show wavelengths of energy that are released 14. What is the length & color of the shortest wavelength in the visible spectrum? Does this color contain more or less energy than yellow (55nm). The shortest wavelength is violet, about 4 nm. Violet contains more energy then yellow. The shorter the wavelength, the more energy. Longer wavelengths contain less energy. 15. What is the first stage of the star cycle? protostar 16. What is the last stage of the star cycle? Black hole, or neutron star if high mass star black dwarf if low mass star 1