2nd Term Final Revision Sheet Students Name: __________________________________________ Grade: 11 A/B Subject: Chemistry Teacher Signature _________________ Page 1 of 9 Chemistry Worksheet (2nd Term) Chapter-18, Lesson-1(The Nature of Chemical Equilibrium) I. MULTIPLE CHOICE _____ 1. A chemical reaction in which products can react to re-form reactants is known as a(n) a. reforming reaction. b. buffered reaction. c. reversible reaction. d. stoichiometric reaction. _____ 2. For any reaction at chemical equilibrium, the concentrations of products and reactants a. are equal. b. change. c. remain unchanged. d. decrease. _____ 3. What symbol in a chemical equation indicates equilibrium? a. b. c. d. _____ 4. Which two processes are at equilibrium in a saturated sugar solution? a. evaporation and condensation b. dissolution and crystallization c. decomposition and synthesis d. ionization and recombination _____ 5. Consider the following equation: reactants products. Which statement is correct? a. The concentration of the reactants is greater than the concentration of the products at equilibrium. b. This is an example of static equilibrium. c. The reverse reaction is favored. d. Both (a) and (c) _____ 6. Which processes are taking place in the system represented by the following equation? 2CO(g) + O2(g) 2CO2(g) a. displacement and reduction b. synthesis and decomposition c. ionization and recombination d. sublimation and evaporation _____ 7. Before a chemical reaction reaches equilibrium, a. the reaction rates of the reactants and products increase. b. the reaction rate of the reactants increases and the reaction rate of the products decreases. c. the reaction rates of the reactants and products decrease. d. the reaction rate of the reactants decreases and the reaction rate of the products increases. _____ 8. In the equation for the equilibrium constant of a reaction, the concentrations of the reactants are represented by a. [W] and [X]. b. [W] and [Y]. c. [X] and [Z]. d. [Y] and [Z]. _____ 9. The use of the square brackets around a chemical formula implies that the concentration is Page 2 of 9 expressed in the unit a. grams per cubic centimeter. c. kilograms per liter. b. kilograms per deciliter. d. moles per liter. II. QUESTION AND ANSWER 1.Write the equilibrium expression for the following hypothetical equation: 3A(aq) B(aq) 2C(aq) 3D(aq) _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ 2. Write the appropriate chemical equilibrium expression for each of the following equations. Include the value of K. (1) N 2 O 4 ( g ) K = 0.1 2 NO 2 ( g ) _______________________________________________________________ _______________________________________________________________ (2) NH 4 OH(aq) NH 4 (aq) OH (aq) K = 2 10 5 _______________________________________________________________ _______________________________________________________________ 3. a. Compare the rates of forward and reverse reactions when equilibrium has been reached. _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ b. Describe what happens to the concentrations of reactants and products when chemical equilibrium has been reached. _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ 4. Consider the following equation: 2NO( g ) O 2 ( g ) 2 NO 2 ( g ) At equilibrium, [NO] = 0.80 M, [O2] = 0.50 M, and [NO2] = 0.60 M. Calculate the value of K for this reaction. Page 3 of 9 _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ Chemistry Worksheet (2nd Term) Chapter-18, Lesson-2(Shifting Equilibrium ) III. MULTIPLE CHOICE _____ 1. If a system that is at equilibrium is disturbed, then it will change in a way that will oppose the a. decomposition of reactants. b. re-formation of reactants. c. stress on the system. d. synthesis of products. _____ 2. By applying Le Châtelier’s principle to a reaction that has come to equilibrium, you can make the reaction a. produce more reactants. b. run to completion. c. reach a new chemical equilibrium. d. All of the above _____ 3. Which of the following is not a stress on an equilibrium reaction involving gases? a. increasing pressure b. raising temperature c. maintaining volume d. varying the concentrations _____ 4. Consider the reaction represented by the equation COg 3H 2 g CH 4 g H 2 Ol Which of the following could you add to the system without affecting the reaction? a. CO(g) b. H2 c. CH2(g) d. H2O(l) _____ 5. Write the equilibrium constant expression for the following equation: Fe (s) 5CO( g ) Fe (CO)3 ( g ) a. [Fe] b. 5[CO][Fe(CO)3] [Fe][5CO] c. [Fe(OH) 3 ] [Fe(CO)3 ] d. [CO]5 Page 4 of 9 _____ 6. If the equation 2COg O 2 g 2CO 2 g is for a system at equilibrium, increasing the pressure will cause the a. quantity of CO(g) to increase. b. quantity of CO2(g) to decrease. c. quantity of CO2(g) to increase. d. quantities of all components in the reaction to remain unchanged. _____ 7. If the equation CH 3 OHg 101 kJ COg 2H 2 g is for a system at equilibrium, increasing the temperature will cause a. [CH3OH] to increase and [CO] to decrease. b. [CH3OH] to decrease and [CO] to increase. c. both [CH3OH] and [CO] to increase. d. the concentrations of all components in the reaction to remain unchanged. _____ 8. The common-ion effect promotes a. dissolution. b. ionization. c. precipitation. d. All of the above _____ 9. You can precipitate silver chloride from a saturated solution of the compound by adding a. CuSO4(aq). b. HCl. c. H2O d. Both (a) and (b) _____ 10. The Haber process applies Le Châtelier’s principle in the manufacturing of a. ammonia. b. liquid hydrogen. c. liquid nitrogen. d. sodium chloride. IV. QUESTION AND ANSWER 1. Consider the following equilibrium equation: energy. At equilibrium, which reaction will be favored (forward, reverse, or neither) when __________________ a. extra CO gas is introduced? ______________________________________________________________ __________________ b. a catalyst is introduced? ______________________________________________________________ Page 5 of 9 __________________ c. the temperature of the system is lowered? __________________________________________________________________ d. the pressure on the system is increased due to a decrease in the container volume? _______________________________________________________________ _______________________________________________________________ ______________________________________________________________ 2. Are pure solids included in equilibrium expressions? Explain your answer. _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ ______________________________________________________________ 3. A key step in manufacturing sulfuric acid is represented by the following equation: 2SO 2 ( g ) O 2 ( g ) 2SO 3 ( g ) 100 kJ/mol To be economically viable, this process must yield as much SO3 as possible in the shortest possible time. You are in charge of this manufacturing process. a. Would you impose a high pressure or a low pressure on the system? Explain your answer. _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ b. To maximize the yield of SO3, should you keep the temperature high or low during the reaction? _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ c. Will adding a catalyst change the yield of SO3? _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ Page 6 of 9 Chapter-18, Lesson-3( Equilibria of Acids, Bases, and Salt ) Grade- 11 V. MULTIPLE CHOICE _____ 1. Which of the symbols below denotes the acid ionization constant? a. K b.Ka c. Kb d. Ka _____ 2. The acid ionization constant for weak acids a. is much greater than 1. b. is exactly equal to 1. c. is much less than 1. d. can be greater or less than 1. _____ 3. A solution that can resist changes in pH is called a(n) a. acidic solution. b. basic solution. c. salt solution. d. buffered solution. _____ 4. Hydrolysis is a reaction that occurs when water molecules a. surround solute particles. b. react with ions of a salt. c. decompose to form H2 gas and O2 gas. d. Both (a) and (c) _____ 5. Salts of weak acids and weak bases can produce a. acidic solutions. b. basic solutions. c. neutral solutions. d. All of the above CH 3 COOH(aq) H 2 O(l ) CH 3 COO- (aq) H 3 O (aq) _____ 6. Which substance, at equilibrium, is likely to have the highest concentration? a. CH3COOH b. CH3COO– c. H2O+ d. Both (b) and (c) _____ 7. When sodium acetate, NaCH3COO, is added to the system, Page 7 of 9 a. b. c. d. both [H3O+] and [CH3COOH] increase. both [H3O+] and [CH3COOH] decrease. [H3O+] increases and [CH3COOH] decreases. [H3O+] decreases and [CH3COOH] increases. _____ 8. An acid and the base that can combine to form the salt CaCl2 are a. HCl and CaOH. b. KCl and CaSO4. c. HCl and H2SO4. d. HCl and Ca(OH)2. _____ 9. What are the conjugate acid-base pairs for the reaction represented by the following equation? B(aq) H 2 O(l ) BH (aq) OH (aq) a. B and H2O; BH+ and OH– b. B and BH+; H2O and OH– c. B and OH–; H2O and BH+ d. None of the above VI. QUESTION AND ANSWER 1. In the space below each of the following equations, correctly label the two conjugate acid-base pairs as acid 1, acid 2, base 1, and base 2. (a) CO 32 (aq) H 3 O (aq) HCO3 (aq) H 2 O(l ) ______________________________________________________________ ______________________________________________________________ (b) HPO24 (aq) H 2 O(l ) OH (aq) H 2 PO 4 (aq) __________________________________________________________________ __________________________________________________________________ 2. Write the formulas for the acid and the base that could form the salt Ca(NO3)2. _______________________________________________________________ _______________________________________________________________ 3. Consider the following equation for the reaction of a weak base in water: NH3 (aq) H 2 O(l ) NH 4 (aq) OH 2 (aq) Write the equilibrium expression for K. _______________________________________________________________ _______________________________________________________________ 4. An unknown acid X hydrolyzes according to the equation in part a below. a. In the space below the equation, correctly label the two conjugate acid-base pairs in this system Page 8 of 9 as acid 1, acid 2, base 1, and base 2. HX(aq) H 2 O(l ) X (aq) H 3 O (aq) _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ b. Write the equilibrium expression for Ka for this system. _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ Page 9 of 9