Name Period Teacher Practice Test: OTHS Academic Chemistry Spring Semester 2017 The exam will have 100 multiple choice questions (1 point each) Formula sheet (see below) and Periodic table will be provided on the exam Gas Laws FORMULA SHEET: Academic Chemistry Spring Semester Exam Bonding # atoms around central atom # lone pairs around central atom 2 0 Linear Shape 2 1 Bent (120 o ) 2 2 Bent (109.5 o ) 3 0 Trigonal planar 3 1 Pyramidal 4 0 Tetrahedral Solutions M= moles solute Mass %= mass solute x 100 L solution mass solution M1V1=M2V2 Acids and Bases ph + poh = 14 [H + ] x [OH - ] = 1.0 x 10 14 ph = - log [H + ] poh = - log [OH - ] n b M a V a = n a M b V b [H+] = 10^-pH [OH-] = 10^-pOH Thermochemistry q = mc T 1
I. Chemical Reactions 1. On which side of the reaction are the reactants? The products? 2. What is a coefficient, and what is it used for? 3. What is a catalyst? How would it be indicated in a chemical equation? What effect does a catalyst have on the rate of a chemical reaction? 4. Which type of reaction uses the activity series? How do you determine if a reaction will occur? 5. Describe a double replacement reaction? Give an example. 6. Describe a single replacement reaction? Give an example. 7. Describe a synthesis reaction? Give an example. 8. Describe a decomposition reaction? Give an example. 9. Describe a combustion reaction? Give an example. 10. List the seven diatomic elements. 11. What is the symbol for aqueous? Gas? Solid? Liquid? 12. Write the balanced equation for the synthesis reaction between magnesium and sulfur: 13. Write the balanced equation for the decomposition reaction of aluminum oxide: 14. Write the balanced equation for the single replacement reaction between potassium and copper (II) chloride: 15. Write the balanced equation for the double replacement reaction between lead (II) iodide and sodium nitrate: 16. Write the balanced equation for the combustion reaction of propane (C 3H 8): 17. Balance the following reaction: AlBr 3 + Cl 2 AlCl 3 + Br 2 18. Balance the following reaction: P 4O 10 + KOH K 3PO 4 + H 2O 19. Balance the following reaction: Ca(OH) 2 + HNO 3 Ca(NO 3) 2 + H 2O 20. Determine whether the following elements have been oxidized or reduced and label the reaction type. 4 Na + O 2 2 Na 2O TYPE of Reaction: S/D/SR/DR Element Ox.# Reactants side Ox.# Products side Lose/Gain e Oxidized/Reduced Na O 2
II. Stoichiometry 21. Stoichiometry problems all have one common step. What is it? 22. In the reaction 4 Fe + 3 O 2 2 Fe 2O 3, what is the mole ratio of iron to iron (III) oxide? 23. In the reaction 2 Al 2O 3 4 Al + 3 O 2, what is the mole ratio of aluminum oxide to oxygen? 24. Consider the reaction N 2 + 3 H 2 2 NH 3. To completely react 8.0 mol nitrogen gas, how many moles of hydrogen gas are required? (24 mol H 2) 25. For the reaction C + 2 H 2 CH 4, how many moles of carbon are required to produce 2.3 mol of methane, CH 4? (2.3 mol C) 26. For the reaction 2 H 2 + O 2 2 H 2O, how many moles of water are produced from 4.00 L of hydrogen gas at STP? (0.179 mol H 2O) 27. For the reaction 2 Na + Cl 2 2 NaCl, how many grams of sodium are required to react completely with 2.00 mol of chlorine gas? (92.0g Na) 28. For the reaction CH 4 + 2 O 2 CO 2 + 2 H 2O, how many liters of CO 2 (at STP) are produced from the combustion of 250. g of methane (CH 4)? (349 L CO 2) 29. For the reaction Cl 2 + 2 KBr 2 KCl + Br 2, how many grams of bromine can be produced from 100. g of potassium bromide? (67.2 g Br 2) 30. For the reaction 2 Mg + O 2 2 MgO, what mass of O 2 is used when 1.6 x 10 22 atoms of Mg are used? (0.43 g O 2) 31. What is the definition of the limiting reactant in a chemical reaction? Excess reactant? 32. If nitrogen is the limiting reactant in the reaction: N 2 + 3 H 2 2 NH 3, which substance(s) will be present when the reaction stops? 33. Consider the reaction 2 H 2 + O 2 2 H 2O. If you start the reaction with 16.0 g hydrogen gas and 68.0 g oxygen gas, (a) what is the limiting reactant? (b) How many grams of water can be produced? (this is your theoretical yield) (76.6 g H 2O) 34. Find the percent yield of water for the above reaction if, in an experiment, a student produced 70.0 g of water. (91.4%) 3
III. Bonding 35. The electrons involved in the formation of a chemical bond are called? 36. A chemical bond resulting from the attraction between positive and negative ions is called? 37. The chemical bond formed when two atoms share electrons is called? 38. Molecular compounds (those which contain covalent bonds) contain what type(s) of elements? 39. Ionic compounds contain what type(s) of elements? 40. Explain the behavior of electrons in metallic bonding. 41. List 7 characteristics of metals. 42. Atoms tend to form bonds so that the number of electrons in the outermost energy levels of each atom is. 43. The elements of the group satisfy the octet rule without forming compounds. 44. How many valence electrons are in an atom of krypton? 45. How many valence electrons are in an atom of sulfur? 46. How many valence electrons are in an atom of phosphorus? 47. How many valence electrons are in an atom of silicon? 48. How many double bonds are in the Lewis structure for Cl 2? 49. How many electrons must be shown in the Lewis structure of the ammonium ion, NH 4+? 50. What is the Lewis structure for CCl 4? 51. Use VSEPR theory to predict the shape of CCl 4. 52. How many single bonds are in the Lewis structure for PF 3? 53. According to VSEPR theory, the shape of PF 3 is? 54. How many double bonds are in the Lewis structure for silicon dioxide, SiO 2? 55. Use VSEPR theory to predict the shape of silicon dioxide. 56. Define hydrogen bonding. What elements does H have to be bonded to? 57. Why are water molecules polar? 58. What is responsible for water s very high boiling point and excellent surface tension? 4
IV. Gas Laws 59. According to the kinetic-molecular theory, how can the particles of a gas be described? 60. Convert 55 o C to Kelvin. (328 K) 61. What instrument measures atmospheric pressure? 62. If the temperature of a fixed quantity of gas decreases and the pressure remains unchanged, what happens to the volume? 63. Why does the air pressure inside the tires of a car increase when the car is driven? 64. At constant temperature, if the volume of a flexible container is increased, how will the pressure change? 65. The volume of a gas is 800.0 ml when the pressure is 2.00 atm. At the same temperature, what is the pressure at which the volume of the gas is 3.50 L? (0.457 atm) 66. The volume of a gas is 2.5 L when the temperature is 8.0ºC. If the temperature is increased to 25.0ºC without changing the pressure, what is the new volume? (2.7 L) 67. A 220. ml volume of gas is measured at 63.0ºC. If the pressure remains unchanged, what is the volume of the gas at standard temperature? (179 ml) 68. On a cold winter morning when the temperature is 11.0ºC, the air pressure in an automobile tire is 1.20 atm. If the volume does not change, what is the pressure after the tire has warmed to 25.0ºC? (1.36 atm) 69. The pressure of a 900. ml sample of gas at 15.0ºC increases from 500. mm Hg to 800. mm Hg. If the volume is unchanged, what is the new temperature in o C? (188 o C) 70. The volume of a sample of oxygen is 700.0 ml when the pressure is 1 atm and the temperature is 37.0ºC. At what Kelvin temperature is the volume 2.40 L and the pressure 0.600 atm? (638 K) 71. A sample of gas at 25.0ºC has a volume of 9.00 L and exerts a pressure of 740. mm Hg. How many moles of gas are in the sample? (0.358 mol) 5
V. Solutions **Make sure you know the definitions of the vocabulary words on p.1 of your Solutions Notes** 72. What factors would increase rate of dissolving a solid in water? 73. If you wanted a solid substance to dissolve slowly, should you use large or small crystals, and should you stir or not? 74. If the amount of solute present in a solution at a given temperature is less than the maximum amount that can dissolve at that temperature, the solution is said to be? 75. If the amount of dissolved solute in a solution at a given temperature is greater than the amount that can permanently remain in solution at that temperature, the solution is said to be? 76. What does the rule like dissolves like mean? 77. What polar solvent is called the universal solvent? 78. Is a substance that is NOT soluble in a polar solvent: polar or nonpolar? 79. Milk is soluble in water because the molecules in milk are: polar or nonpolar. 80. As pressure increases, what happens to the solubility of gases in liquids? 81. As temperature increases, what happens to the solubility of gases in liquids? 82. In most cases, as temperature increases, what happens to the solubility of solids in liquids? Write the products for each of the following reactions, balance, & label each product with (aq) or (s). 83. Pb(NO 3) 2(aq) + KCl (aq) 84. BaBr 2(aq) + Na 2SO 4(aq) Use the solubility curves on the formula sheet to answer the questions. 85. At 70 o C, how much sodium chloride can be dissolved in 100 g water? 86. At 70 o C, how much sodium chloride can be dissolved in 400 g water? 87. A saturated solution of potassium nitrate is made with 100 g water at 60 o C. How much potassium nitrate would crystallize out if the solution is cooled to 40 o C? 88. What is the molarity of a solution that contains 1.4 mol NH 3 in 3.0 L solution? (0.47 M) 89. What is the molarity of a solution that contains 65.0 g KCl in 3.00 L solution? (0.291 M) 90. How many moles of HCl are present in 1.50 L of a 0.880 M HCl solution? (1.32 mol) 91. What is the mass % of a solution composed of 15 g salt in 100 g water? Be careful! (13%) 92. How much NaCl is dissolved in a 9.0% NaCl solution if the total solution mass is 100. g? (9.00 g) 93. You have a solution of 18.0 M HCl and you want to make a dilution so that you have 2000. ml of a 1.00 M solution. How much of the original acid will be required? How much water will you have to mix with it? (111 ml HCl, 1889 ml H 2O) 6
VI. Acids and Bases 94. How do acids taste? 95. What color does litmus paper turn in an acid? In a base? 96. Acids react with bases to produce what two products? 97. How do bases taste? 98. Determine the formulas, given the following names: a. phosphoric acid c. hydrofluoric acid b. sulfurous acid d. magnesium hydroxide 99. Determine the names, given the following formulas: a. NH 3 d. NaOH b. H 3PO 3 e. H 2CO 3 c. HCl 100. What is an electrolyte? What 3 types of substances form electrolytes when dissolved in water? 101. The substances produced when Ba(OH) 2 neutralizes H 2SO 4 are? 102. What is the formula for finding the ph of a solution if given [H + ]? 103. What is the ph of an acidic solution, relative to 7? The poh of an acidic solution relative to 7? 104. What is the ph of a basic solution, relative to 7? The poh of a basic solution relative to 7? 105. What is the ph of a solution of HCl with [H + ] = 1.0 x 10 4 M? 106. If [OH - ] = 4.7 x 10 5 M, what is the poh of the solution? 107. Determine whether the following solutions are acidic, basic, or neutral. a. [OH - ] = 1.26 x 10-5 M c. [H + ] = [OH - ] b. ph = 3.3 d. poh = 5 108. What are the two products in a neutralization reaction? 109. Write and balance the chemical reaction between nitric acid and calcium hydroxide: 110. Write and balance the chemical reaction between sulfuric acid and potassium hydroxide: a. What is the molarity of H 2SO 4 if 125 ml is needed to neutralize 65.0 ml of 0.25 M KOH? b. What is the molarity of KOH if 50.0 ml is needed to neutralize 100 ml of 3.0 M H 2SO 4? 7
VII. Thermochemistry 111. Define the following terms and be able to recognize them on an energy graph (like the one on page 2 of your notes): a. Activation energy- b. Activated complex- c. Change in enthalpy ( H)- d. Reactants- e. Products- 112. Determine whether the following are endothermic or exothermic: a. ΔH products ΔH reactants < 0 c. The surroundings lose heat as the reaction occurs. b. ΔH reaction = 355 kj/mol d. 2 HCl + 44 kcal H 2 + Cl 2 107. 113. Define each phase change and label as exothermic or endothermic: Melting: Freezing: Condensing: 114. How is evaporation similar to and different from boiling? Boiling: Deposition: Sublimation: 115. What is the specific heat of a substance if it takes 250 J of heat energy to raise the temperature of a 20. g sample from 20 o C to 45 o C? (0.50 J/g o C) 116. A 100.0 g sample of a metal with a specific heat of 0.836 J/g o C is heated from 10.0 o C to 80.0 o C. How much thermal energy in Joules did it absorb? (5852 J) 8