Download General Chemistry - Answers Key for Exam 1 - Fall 2019 | CHEM 1202 and more Exams Chemistry in PDF only on Docsity!
FORM 1
KEY
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Exam Length : 70 minutes
Allowed Materials: You may use a calculator, but it must not contain written information (text) or have equations programmed into it to help solve the test problems. You are not allowed to use any written notes (paper or electronic). You are not allowed to use a cell phone, computer, tablet, etc. during the exam. Electronics and papers must be stored in a bag or backpack during the exam. Any instances of academic misconduct (cheating) will be reported to Student Advocacy and Accountability.
It is to your advantage to submit an answer for every question, even if you are unsure of the answer. It is a good strategy to first answer the problems you understand best – in other words do the easy and quick problems first. If you have extra time at the end of the exam, use this time to check your work and answers.
A periodic table is located at the back of the exam. R = 0.08206 L-atm/mol-K
Multiple Choice: Choose the answer that best completes the statement or answers the question.
- At equilibrium, ________.
A) all chemical reactions have ceased
B) the rates of the forward and reverse reactions are equal
C) the value of the equilibrium constant is 1 D) the limiting reagent has been consumed
E) the value of the equilibrium constant is 7.
Discussed in Lecture 1, See Lecture 2 Notes Textbook; page 624, Chapter Summary and Key Terms for Section 15.1 (page 654) Homework 1 Problem 2, “Give It Some Thought 15.1” Homework 1 Problem 20, “Chapter 15 Reading Question 11” Homework 1 Problem 45, “Pause and Predict Video Quiz: Equilibrium and Equilibrium Constants”
- What is the conjugate acid of HCO3-?
A) CO22-
B) H2CO
C) HCO22-
D) CO32-
E) none of the above
See Lecture 5 Notes Textbook; pages 668-670, Sample Exercise 16.1, Sample Exercise 16.2, Chapter Summary and Key Terms for Section 16.2 (page 707) Homework 2 Problem 18, “Conjugate Pairs” Homework 2 Problem 19, “Problem 16.18 – Enhanced – with Feedback” Homework 2 Problem 25, “Chapter 15 Reading Question 2” Homework 2 Problem 26, “Chapter 15 Reading Question 12”
- The equilibrium expression for Kp for the reaction below is ________.
2O3 (g) 3O2 (g)
A)
B)
C)
D)
E)
See Lecture 1 Notes, Lecture 2 Notes Textbook pages 630-631, Chapter Summary and Key Terms for Section 15.2 (page 654) Homework 1 Problem 24, “Problem 15.4 – Enhanced – with Feedback” Homework 1 Problem 28, “The Equilibrium-Constant Expression”
- The equilibrium-constant expression for the reaction
Ti (s) + 2Cl2 (g) TiCl4 (l)
is given by
A)
B)
C)
D) [Cl2 (g)]-
E)
See Lecture 2 Notes, Lecture 3 Notes Textbook pages 636-638, Sample Exercise 15.5 (page 637), Chapter Summary and Key Terms for Section 15.4 (page 655) Homework 1 Problem 7, “Give It Some Thought 15.8” Homework 1 Problem 13, “Chapter 15 Reading Question 6” Homework 1 Problem 29, “Chapter 15 Reading Question 15”
- For the endothermic reaction
CaCO3 (s) CaO (s) + CO2 (g)
Le Châtelier's principle predicts that ________ will result in an increase in the number of moles of
A) increasing the temperature
B) decreasing the temperature C) increasing the pressure D) removing some of the CaCO 3 (s)
E) none of the above
See Lecture 3 Notes, Lecture 4 Notes Textbook pages 649-651, Sample Exercise 15.12 (page 650), Chapter Summary and Key Terms for Section 15.7 (page 655) Homework 1 Problem 18, “Chapter 15 Reading Question 10” Homework 1 Problem 37, “Applying Le Châtelier’s Principle” Homework 1 Problem 48, “Volume, Temperature, and Le Châtelier’s Principle Homework 2 Problem 1, “Pause and Predict Vidio Quiz: Le Châtelier’s Principle Demonstrated with a Gas Phase Equilibrium” Homework 2 Problem 2, “Problem 15.62 – Enhanced – with Feedback Homework 2 Problem 3, “Problem 15.64 – Enhanced – with Feedback Homework 2 Problem 4, “Problem 15.68 – Enhanced – with Feedback
- Consider the following chemical reaction:
CO (g) + 2H2(g) CH3OH(g)
At equilibrium in a particular experiment, the concentration of CO was 0.015 M and H2 was
0.36 M. What is the equilibrium concentration of CH3OH? The value of Kc for this reaction is
14.5 at the temperature of the experiment.
A) 14.
B) 7.61 × 10-
C) 2.82 × 10-1^ (should have read 2.82× 10
D) 3.72 × 10-
E) 1.34 × 10-
Because there was an error in the answer, this problem was treated as a bonus question. If you selected the answer closest to the correct answer, you received bonus points. If you did not select this answer, you did not lose any points.
See Lecture 3 Notes, Lecture 4 Notes Textbook pages 642-644, Sample Exercise 15.10 (page 642), Sample Exercise 15.11 (page 643)
- At 400 K, the equilibrium constant for the reaction
Br2 (g) + Cl2 (g) 2BrCl (g)
is Kp = 7.0. A closed vessel at 400 K is charged with 1.00 atm of Br2 (g), 1.00 atm of Cl2 (g),
and 2.00 atm of BrCl (g). Use Q to determine which of the statements below is true.
A) The equilibrium partial pressures of Br2, Cl2, and BrCl will be the same as the initial values.
B) The equilibrium partial pressure of BrCl (g) will be greater than 2.00 atm.
C) The equilibrium partial pressure of Br2 will be greater than 1.00 atm.
D) At equilibrium, the total pressure in the vessel will be less than the initial total pressure.
E) The reaction will go to completion since there are equal amounts of Br2 and Cl2.
See Lecture 3 Notes, Lecture 4 Notes Textbook pages 640-642, Sample Exercise 15.9 (page 642), Chapter Summary and Key Terms for Section 15.6 (page 655) Homework 1 Problem 15, “Chapter 15 Reading Question 8” Homework 1 Problem 33, “The Reaction Quotient” Homework 1 Problem 34, “Smart Figure: 15.9” Homework 1 Problem 36, “Equilibrium Constant and Reaction Quotient Homework 1 Problem 44, “Chapter 15 Reading Question 18”
- A Br∅nsted-Lowry acid is defined as a substance that ________.
A) increases Ka when placed in H2O
B) decreases [H+] when placed in H2O
C) increases [OH-] when placed in H2O
D) acts as a proton acceptor
E) acts as a proton donor
See Lecture 5 Notes Textbook; pages 667-668, Sample Exercise 16.2, Chapter Summary and Key Terms for Section 16.2 (page 707) Homework 2 Problem 19, “Problem 16.18 – Enhanced – with Feedback” Homework 2 Problem 24, “Problem 16.14”
- Which reaction will shift to the right in response to a decrease in volume?
A) N2 (g) + 3H2 (g) 2NH3 (g)
B) H2 (g) + Cl2 (g) 2 HCl (g)
C) 2 SO3 (g) 2 SO2 (g) + O2 (g)
D) 2HI (g) H2 (g) + I2 (g)
E) 2 Fe2O3 (s) 4 Fe (s) + 3O2 (g)
See Lecture 3 Notes Textbook pages 644-648, Sample Exercise 15.12 (page 650), Chapter Summary and Key Terms for Section 15.7 (page 655) Homework 1 Problem 19, “Analysis of Equilibria” Homework 1 Problem 37, “Le Châtelier’s Principle”
Homework 1 Problem 47, “Smart Figure: Le Châtelier’s Principle”
Homework 1 Problem 48, “Temperature, and Le Châtelier’s Principle” Homework 2 Problem 2, “Problem 15.62 – Enhanced – with Feedback Homework 2 Problem 3, “Problem 15.64 – Enhanced – with Feedback Homework 2 Problem 4, “Problem 15.68 – Enhanced – with Feedback Homework 2 Problem 5, “Give It Some Thought 15.11” Homework 2 Problem 6, “Problem 15.10”
- The concentration of iodide ions in a saturated solution of silver iodide is ________ M. The solubility product constant of AgI is
A) 3.8 × 10-
B) 3.0 × 10-
C) 9.1 × 10-
D) 3.5 × 10-
E) 1.4 × 10-
See Lecture 4 Notes Textbook pages 739-743, Sample Exercise 17.12 (page 742), Chapter Summary and Key Terms for Section 17.4 (page 757) Homework 2 Problem 8, “Introduction to Solubility and the Solubility Product Constant” Homework 2 Problem 9, “The Solubility Product in Medicine” Homework 2 Problem 13, “Chapter 17 Reading Question 7”
- In which of the following aqueous solutions does the weak acid exhibit the highest percentage ionization?
A) 0.01 M H 2 SO 3 ( = 1.4 × )
B) 0.01 M HCN ( = 6.2 × )
C) 0.01 M H 2 CO 3 ( = 4.5 × )
D) 0.01 M HC 3 H 5 O 2 ( = 1.3 × )
E) 0.01 M HOCl ( = 3.5 × )
See Lecture 6 Notes Textbook pages 682-683, Sample Exercise 16.11 (page 683), Sample Exercise 16.13 (pages 686-687), Chapter Summary and Key Terms for Section 16.6 & 16.7 (page 707) Homework 2 Problem 43, “Percent Ionization”
- A- is a weak base. Which equilibrium corresponds to the equilibrium constant Ka for HA?
A) HA (aq) + H2O (l) H2A+^ (aq) + OH- (aq)
B) A- (aq) + H3O+ (aq) HA (aq) + H2O (l)
C) HA (aq) + H2O (l) H3O+ (aq) + A- (aq)
D) A- (aq) + H2O (l) HA (aq) + OH- (aq)
E) A- (aq) + OH- (aq) HOA2- (aq)
See Lecture 5 Notes, Lecture 6 Notes, Lecture 7 Notes Textbook pages 668-669, 680-681, 690
- What is the pOH of an aqueous solution at 25.0 °C that contains 2.50 × 10-4 M hydronium ion?
A) 3.
B) 4.
C) 2.
D) 10.
E) 7.
See Lecture 5 Notes Textbook pages 672-677, Sample Exercise 16.5 (page 674), Sample Exercise 16.6 (page 675), Sample Exercise 16.7 (page 677), Chapter Summary and Key Terms for Section 16.3, 16.4 (page 707) Homework 2 Problem 28, “Problem 16.30 – Enhanced – with Feedback” Homework 2 Problem 29 , “Chapter 16 Reading Question 3”
Homework 2 Problem 30. “Chapter 16 Reading Question 13”
Homework 2 Problem 32 , “Give It Some Thought 16.5”
Homework 2 Problem 35 , “Problem 16.36”
Homework 2 Problem 36. “Chapter 16 Reading Question 14”
- Using the data in the table, which of the conjugate bases below is the strongest base?
A) OAc-
B) C7H5O2-
C) NO2-
D)
E) OAc- and C7H
See Lecture 7 Notes Textbook pages 690-695, Suggested Problem 16.76, Suggested Problem 16.78, Chapter Summary and Key Terms for Section 16.8 (page 707)
- Bonus (In Class) How does increased CO 2 concentration in the atmosphere impact sea creatures that build shells?
A) Carbon dioxide is toxic to all sea life
B) Carbon dioxide displaces oxygen in seawater
C) Carbon dioxide dissolves in seawater, producing carbonic acid, which lowers the pH of
seawater
D) Rising global temperatures increase human demand for shellfish
E) Carbon dioxide dissolves in seawater, producing carbonate, increasing the pH of seawater
This was discussed in class (Lecture 6).
