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Unit 1 ExamCover Page
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Section I15 Multiple-Choice Questions
(Time—30 minutes)YOU MAY NOT USE YOUR CALCULATOR FOR SECTION I
Note: For all questions, assume that the temperature is 298 K, the pressure is 1.00 atmosphere, and solutions are aqueous unless otherwise specified.
Directions: Each of the questions or incomplete statements below is followed by four suggested answers or completions. Select the answer that is best in each case and then fill in the
corresponding circle on the answer sheet.
Multiple-Choice (15 questions)
1. (1) Through spectral analysis, it’s determined that an atom has an atomic mass of 36 and a net charge of +2. Which of the following sets of subatomic particles could represent this ion?
a. 18 protons, 18 neutrons, 18 electronsb. 18 protons, 20 neutrons, 18 electronsc. 18 protons, 18 neutrons, 16 electronsd. 16 protons, 18 neutrons, 14 electrons
2. (2) Which of the four particulate diagrams best shows the formation of water vapor from hydrogen gas and oxygen gas in a rigid container at 145 ˚C?
Use the table below to answer questions #3
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Element # of electron
s
# of neutron
sZinc 30 35Calcium 18 40Vanadium
20 38
Copper 29 37
3. (1) Using the data of different ions in the table above, which of the following atoms would be the lightest?
a. Zincb. Calciumc. Vanadiumd. Copper
4. (1) In a particular reaction, 2.0 moles of NaOH are reacted with 18 g of water. If both reactants are used up completely during the reaction, what do you expect the total mass of the products to be?
a. 18 gb. 40 gc. 80 gd. 98 g
5. (1) What type of reaction is occurring the chemical equation below?
Ca(C2H3O2)2 + Na2CO3 CaCO3 + 2 NaC2H3O2
a. Single Displacementb. Double Displacementc. Combustiond. Synthesis
6. (2) Artificial sweeteners are the latest trend in minimizing glucose intake. 1 g of which of the following compounds, found in many artificial sweeteners, would contain the most number of molecules?
a. [Sucrose, 180 g/mol] C6H12O6
b. [Methanol, 32 g/mol] CH3OHc. [Aspartame; 294 g/mol] C14H18N2O5
d. [Water, 18 g/mol] H2O
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7. (2) Glucose (C6H12O6) is the most common molecule humans use as a source of energy. However, this compound has many structural forms resulting in slightly different chemical behavior. What is the molar mass of the empirical formula of glucose?
a. 30 g/molb. 60 g/molc. 90 g/mold. 180 g/mol
8. (3) 2 moles of a hydrocarbon combusts completely with 7 moles of oxygen gas, producing 4 moles of carbon dioxide and 6 moles of water. What is the formula of the hydrocarbon?
a. CHb. CH2
c. CH3
d. C2H6
9. (2) All of the reactions represented above occur in an aqueous solution of oxalic acid. Which of the following represent a Bronsted-Lowry conjugate acid-base pair?
a. H2C2O4 (aq) and C2O42- (aq)
b. HC2O4- (aq) and C2O4
2- (aq)c. HC2O4
- (aq) and H2O (aq)d. H3O+ (aq) and OH- (aq)
10. (2) Imagine you have 1 L of each of the following solutions. Based on the information below, which of the following would have the lowest concentration of sodium ions?
a. 0.40 M NaBrb. 0.20 M NaClc. 0.30 M Na2Od. 0.10 Na3P
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11. (2) Which of the diagrams below would best represent the dissolution of HNO3 in water?
12. (1) Of the species below, only __________ is not an electrolyte.a. HClO4
b. Rb2SO4c. CO2
d. NH3
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13. (3) Beaker X and beaker Y each contain 1.0 L of solution, as shown above. A student combines the solutions by pouring them into a larger, previously empty beaker Z and observes the formation of a white precipitate. Assuming that volumes are additive, which of the following sets of solutions could be represented by the diagram above?
Beaker X Beaker Y Beaker Za. 4.0 M NaCl 4.0 M AgClO3 8.0 M NaClO3 and AgCl(s)b. 4.0 M NaCl 4.0 M AgClO3 4.0 M NaClO3 and AgCl(s)c. 4.0 M NaCl 4.0 M AgClO3 2.0 M NaClO3 and AgCl(s)d. 4.0 M NaCl 2.0 M AgClO3 1.0 M NaClO3 and AgCl(s)
Questions 14-15 refers to the table below
During a lab you are given four different sets of reactants, which are shown in the table below. When combined, all reactions undergo double displacement reactions.
Reaction # Reactant A Reactant B1 1.0 M K2SO4 2.0 M Hg2CO3
2 1.0 M Na3PO4 2.0 M KOH3 2.0 M LiCl 1.0 M KBr4 1.0 M KOH 1.0 M HBr
14. (2) Which reaction would you expect to have a neutral pH at the equivalence point?a. Reaction 1b. Reaction 2c. Reaction 3d. Reaction 4
15. (3) One of these reactions forms a precipitate. In which reaction would you expect to see this precipitate form?
a. Reaction 1b. Reaction 2c. Reaction 3d. Reaction 4
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Section IIConstructed-Response Questions
(Time—30 minutes)YOU MAY USE YOUR CALCULATOR FOR SECTION II
Directions: Question 1 is a long constructed-response question that should require about 20 minutes to answer. Question 2 is a shot constructed-response question that should required about seven minutes to answer. Read each question carefully and write your response in the space provided following each question. Your responses to these questions will be scored on the basis of the accuracy and relevance of the information cited. Explanations should be clear and well organized. Specific answers are preferable to broad, diffuse responses. For calculations, clearly show the method used and the steps involved in arriving at your answers. It is to your advantage to do this, since you may obtain partial credit if you do and you will receive little or no credit if you do not.
Volume of KOH Added (mL) pH of Solution0 4.0
2.0 4.54.0 5.06.0 5.58.0 6.0
10.0 6.512.0 7.014.0 7.516.0 8.0
1. A student performs a titration experiment in which the pH of a solution is monitored as KOH is added to 25.0 mL of HNO3 in a flask with a drop of phenolphthalein. No precipitate is formed in the reaction but the data collected from the experiment is shown in the table above.
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a. As the KOH is added to the solution, a single chemical reaction is occurring. In the space below, write the molecular, ionic and net ionic equation for this reaction. Place a box around the net ionic equation.
b. After 4.0 mL of KOH have been added, what species is more present in solution, H+ or OH-. Explain your answer using the data above.
c. The concentration of the KOH added is 0.80 M. What is the concentration of HNO3 in the flask? Show all calculations
d. The student performs the experiment a second time but some of the KOH that they drip through the buret misses the flask. How would this error affect the final concentration of HNO3 the student calculates? Explain your answer.
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2. When Aluminum metal and liquid Bromine are mixed, a violent exothermic reaction occurs that reaches such a high temperature the Aluminum metal melts giving off sparks, heat and light. The equation that occurs for this reaction is shown below.
Al + Br2 AlBr3
a. Balance this equationb. If 10.0 g of Al react with 40.0 g of Br2, what is the limiting reactant?c. How much excess reactant will be leftover at the end of the reaction?
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