Grade-11-Chemistry-Revisionsheet

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2nd Term Final
Revision Sheet
 Students Name: __________________________________________
 Grade: 11 A/B
 Subject: Chemistry
Teacher Signature
_________________
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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
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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)
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_______________________________________________________________
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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 )
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_______________________________________________________________


(2) NH 4 OH(aq) 
 NH 4 (aq)  OH (aq)
K = 2  10 5
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_______________________________________________________________
3. a. Compare the rates of forward and reverse reactions when equilibrium has been reached.
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b. Describe what happens to the concentrations of reactants and products when chemical
equilibrium has been reached.
_______________________________________________________________
_______________________________________________________________
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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.
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_______________________________________________________________
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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
COg   3H 2 g  
 CH 4 g   H 2 Ol 
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
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_____ 6. If the equation 2COg   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 OHg   101 kJ 
 COg   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?
______________________________________________________________
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__________________ 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.
_______________________________________________________________
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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?
_______________________________________________________________
_______________________________________________________________
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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,
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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 )
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______________________________________________________________


(b) HPO24 (aq)  H 2 O(l ) 
 OH (aq)  H 2 PO 4 (aq)
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__________________________________________________________________
2. Write the formulas for the acid and the base that could form the salt Ca(NO3)2.
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_______________________________________________________________
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
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as acid 1, acid 2, base 1, and base 2.
HX(aq)  H 2 O(l )  X  (aq)  H 3 O  (aq)
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_______________________________________________________________
_______________________________________________________________
b. Write the equilibrium expression for Ka for this system.
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