ACS PracticeTest 2

1

ACS Practice Test 2 Acids & Bases:

1. HCl is a strong acid. What is the pH p H of 200 mL of 0.002 M HCl? (A) 2.0 (B) 2.7 (C) 3.4 (D) 4.0 2. The pH of a 0.03 M HCl solution is (A) 1.5 (B) 2.5 (C)

3.5

(D)

12.5

3. The pH of a 1.0  10 – 3 M Ba(OH)2 solution at 25 °C is (A) 2.7 (B) 3.0 (C) 11.0 (D) 11.3 4. The pH of a solution is 5. If the pH of this solution is decreased to 2, b y what factor is the concentration of hydrogen ion increased? (A) 2 1/2 (B) 3 (C) 10 (D) 100 (E) 1000 5. What is the pH of a 0.01 M NaOH solution? 12 (A) 10 – 12 (B) 12 (C) 12 – 12

(D)

2

(E)

– 2

Atomic Structure:

6. Which particle has the smallest mass? (A)hydrogen atom

(B)alpha particle

(C)beta particle

(D)proton

(E)neutron

7. A sodium ion differs from a sodium atom in that the sodium ion (A) (D)

is more reactive. (B) exists only in solution.

has fewer electrons. (C) is an isotope of sodium. (E) has a negative charge on its nucleus.

8. What is the number of unpaired electrons in an isolated free iron atom (atomic number 26) in the ground state? (A) zero (B) two (C) three (D) four 9. Which ion has twenty – six six electrons? (A)

Cr 2+

(B)

Fe2+

Ni2+

(C)

(D)

Cu2+

10. The element in Period 5, Group 3A, has the outer electron configuration (A)

5 s25 p1 (B)

3 s23 p5 (C)

3 s23 p3 (D)

5 s25 p3

Bonding:

11. Use the section of a periodic table to determine the type of bond that will form between W and E.

Fir st Per iod Second Per Per iod Third Period Fourth Per Per iod

(A)

I

II

M ain Gr oups ups I II I V V VI VI

X

Q

M

Y

R

N

Z

S

covalent

(B)

T

U

V W

electronic

V I I (O) D

J

E

K

G

L

(C)

ionic

(D)

metallic

(E)

van der Waals

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2 12. Which characteristic is generally true of nonmetallic oxides? (A)They are in general ionic compounds. (B)They are in general covalent compounds. (C)They react with water to form bases. (D)They cannot be prepared directly from the elements. (E)They react with acids to form a salt and water 13. Which atom description represents an element that could form a covalent compound with an atom of a nonmetal? (A )

(B)

(C)

(D)

Nucleus

n=1

n=2

n=3

n=4

3 p, 4 n

2e

Nucleus

n=1

n=2

n=3

n=4

11 p, 12 n

2e

8e

1e

Nucleus

n=1

n=2

n=3

n=4

29 p, 35 n

2e

8e

18 e

1e

Nucleus

n=1

n=2

n=3

n=4

8 p, 10 n

2e

6e

14. Hydrogen bonding is shown by molecules containing hydrogen attached to (A) highly electronegative atoms. (B) highly electropositive atoms. (C) any atoms. (D) only oxygen. 15. Which best represents hydrogen bonding in liquid methanol (CH3OH)?

(A)

(B)

H

O

H

H

O

C

H

H

C

H

H

H

H

O

O

H

H

C

C

H

H

H

H

H H

(C) H

H

H

H

C

C

O

H

O

H

H

(D)

H

H

H

C

O

H

H

H

H

C

O

H







3

(II) sulfate is electrolyzed between inert electrodes. Assuming no gas evolution at 17. A solution of copper (II) the cathode, for how many seconds must a current of 1.93 A flow to deposit 0.640 g of copper metal? Atomic Molar Mass

63.5 g·mol – 1

Cu

Conversion Factor 95,500 C = 1 F 1 F (A)

9650 s (B)

2000 s (C)

1930 s (D)

1000 s

(E)

965 s

18. How many grams of aluminum is deposited de posited electrolytically in 30 min by a current of 40 A? Atomic Molar Mass 27.0 g·mol – 1

Al

Conversion Factor (A)

3.0 g

(B)

6.7 g

(C)

95,500 C = 1 F 1 F 9.0 g (D) 13.5 g

(E)

27.0 g

19. How many coulombs are required to liberate one mole of iron from a solution of Fe2(SO4)3? 96500 96500 (A)96500 (B)6  96500 (C) (D) (E) 3  96500 6 3 20. Two electrolytic cells, one containing a silver nitrate solution and the other containing a copper coppe r (II) sulfate solution, were connected so that the same current passed through both cells. A current was passed through both solutions until 53.95 g of silver had been deposited. What mass, in grams, of copper was deposited? Atomic Molar Masses

(A)

Ag Cu 15.9

107.9 g·mol – 1 63.5 g·mol – 1 (B) 27 (C)

31.8

(D)

54

(E)

63.6

Equilibrium:

21. The value of the equilibrium constant K constant K for for a reaction at equilibrium is altered by (A)changing the effective concentration of reactants. (B)changing the effective concentration of products. (C) changing the temperature. (D) adding a catalyst. (E) adding water.







4 23. The reversible reaction. 2H2 + CO   CH3OH(g) + heat is carried out by mixing carbon monoxide monox ide and hydrogen gases in a closed vessel under high pressure with a suitable catalyst. After equilibrium is established at high temperature and p ressure, all three substances are present. If the pressure on the s ystem is lowered, with the temperature kept constant, what will be the result? (A) The amount of CH3OH will be increased. (B) The amount of CH3OH will be decreased. (C) The amount of each substance will be unchanged. (D) The amount of each substance will be increased. (E) The result cannot be predicted from the information given. 24. In which gas reaction would a change in pressure have no appreciable effect upon the composition of the equilibrium mixture? (A)

H2 + I2

(B)

2SO2 + O2

 

2SO3

(C)

4HCl + O2

 

2Cl2 + 2H2O

(D)

N2 + 3H2

(E)

2NO + O2

 

2HI

 

2NH3

 

2NO2

25. The numerical value of the equilibrium constant for any chemical change is affected by changing (A) the catalyst. (B) the concentration of the products. (C) the concentration of reacting substances. (D) the pressure. (E) the temperature Formulas & Equations:

26. The ions present in solid silver chromate Ag2CrO4 are (A) Ag+ and CrO42 – (B)Ag2+ and CrO44 – (C)Ag+, Cr 6+, and O2 –

(D)Ag+, Cr 3+, and O2 –

27. Substances that contain water incorporated in the crystal in definite proportions by weight are (A)anhydrous. (B)amorphous. (C)hydrates. (D)polymorphous. (E)zeolites. 28. Three compounds having the formulas NaCl, CaCl2, and AlCl3 exist. Comparison of these formulas indicates that (A) the chlorine atom can accept l, 2, or 3 electrons. (B) combined chlorine has a positive oxidation number. (C) the combining capacity of chlorine varies. (D) the combining capacities of the metals are different. (E) each metal has a variable combining capacity.







5 (C)carbon dioxide decomposes, but that the relative amounts of CO2, CO, and O2 involved in the reaction are a function of conditions. (D)regardless of conditions, the decomposition of l mol of CO2 will yield l mol of CO and O2. (E)the tendency of CO2 to decompose is equal to the tendency of CO and O2 to combine.

1/2 mole

of

WE HAVE DONE ALL THE QUESTIONS ON “FORMULAS & EQUATIONS” IN THE DATA BANK!

Gases:

30. At constant volume, the pressure of gas Y increases with increasing temperature because as the temperature increases, (A) molecules of Y move faster. (B) the molecular volume of Y increases. (C) the mass of Y molecules increases. (D) molecular collisions are more elastic. (E) molecules are closer together. 31. A student collected 40 mL of H2 gas when the temperature was 20 °C and the pressure was 720 mmHg. The next day the temperature was 20 °C, but he had only 38.4 mL of gas. The new pressure is (A)691 mmHg (B)700 mmHg (C)721 mmHg (D)750 mmHg (E)760 mmHg 32. A container holds 3.0 g of o f hydrogen. If it is evacuated and filled with methane, CH4, at the same temperature and pressure, what mass of methane does it now hold? Atomic Molar Masses

(A)

16 g

C H (B)

12.0 g·mol – 1 1.0 g·mol – 1 l9 g (C) 22.4 g (D)

24 g

(E)

48 g

33. If the temperature of 10.0 L of a gas is decreased from 0.00 °C to 27.3 K and the pressure is increased from 10.0 atm to 100.0 atm, the new volume will have a value nearest to (A) 1000 L. (B) 10.0 L. (C) 1.00 L. (D) 0. 100 L. (E) 27.3 L. 34. Both the pressure and the absolute temperature of a certain gas sample are doubled. In the absence of dissociation, the density of the gas is (A)quadrupled. (B)doubled. (C)unchanged. (D)decreased by one – fourth fourth (E)decreased by one – half. Introductory Concepts:

35. Most nonmetals (A) are relatively good reducing agents. (B) form hydroxides that are basic or amphoteric. (C) are lustrous and highly conductive. (D) form anions more readily than cations. (E) have only 1, 2, or 3 electrons in the outermost shell.







6 (A)a low atomic number (B)a high ratio of protons to neutrons electrons (D)fewer than three valence electrons 38. Which is correct for most metals? (A)form complex ions (B)have variable valence (D)are amphoteric (E)give up electrons to chlorine

(C)more than five valence

(C) have colored ions

39. Antimony reacts spontaneously with chlorine to form antimony chloride. The reaction would proceed with reduced velocity if one were to (A) use smaller particles of antimony. (B) use larger particles of antimony. (C) increase the pressure on the chlorine gas before the antimony is introduced. (D) increase the temperature of the chlorine. (E) carry out the reaction in sunlight. Kinetics:

40. no catalyst present catalyst present

A

+

B C

+

D

reaction coor dinate

Which statement concerning the reaction coordinate diagram is true? (A) The catalyst decreases the activation energy. (B) The reaction is endothermic. (C) The addition of a catalyst slows this reaction. (D) A and B have lower potential energy than C and D. 41. Which is necessarily true of the role of a cat alyst in equilibrium? (A) It affects the equilibrium constant. (B) It shifts equilibrium to the products. (C) It decreases the time interval necessary for establishment of equilibrium. (D) It has a greater effect on the forward reaction rate than on the reverse reaction rate.









7 42. Two reaction pathways are indicated: one for the uncatalyzed reaction and one for the reaction in the presence of a catalyst.

E

B E

C A

D X + YZ ® XZ + Y reaction coordinate

The activation energy in the presence of this catalyst is represented by (A) (B) (C) (D) (E) A B C D

E minus B

43. The following mechanism has been proposed for the formation of ethylbenzene: CH3CH2Br + AlBr 3  AlBr 4 – + CH3CH2+ CH3CH2+ + C6H6  C6H6CH2CH3+ C6H6CH2CH3 + AlBr 4 –  AlBr 3 + HBr + C6H5CH2CH3 Which substance serves as the catalyst? (A) AlBr 3 (B) AlBr 4 –

(C)

CH3CH2+

(D)

44. The table presents data for the reaction: 2H2(g) + 2NO(g)

k 1    

2H2O(g) + N2(g)

The temperature of the reaction is constant. The initial rate is in arbitrary units.

C6H6CH2CH3+







8 (A) The electrolysis of 1 M HCl between inert electrodes requires a potential of 1.3 V, while while the electrolysis of 0.01 M HCl requires 1.7 V. (B) Hydrochloric acid is completely dissociated in dilute solution. (C) The anode product from from the 1 M solution is a greenish yellow yellow gas while while that from from the 0.01 M solution is a colorless, odorless gas. (D) Two gases are formed in the electrolysis of both solutions but the greenish – yellow yellow gas dissolves in the more dilute solution so that only onl y the colorless gas is observed. (E) When either of two ions may be oxidized at an anode, the one requiring the lowest potential will be oxidized and this potential depends on the concentration as well as on the relative ease of oxidation. 46. Anhydrous calcium chloride, frequently used as a drying agent for gases and liquids in the laboratory, readily deliquesces in the air. Which conclusion can be drawn from this fact? (A)A concentrated calcium chloride solution has a vapor pressure that is greater than the actual pressure of the water vapor in the air. (B)A concentrated calcium chloride solution has a v apor pressure that is less than the actual pressure of the water vapor in the air. (C)The deliquescence of calcium chloride is not related to the humidity. (D)Calcium chloride forms a solution with evolution of heat. (E)Calcium chloride is not very soluble in water. 47. Which would be most effective for drying moist carbon dioxide gas? (A) solid calcium oxide (B) activated charcoal (C) a concentrated sodium hydroxide solution (D) concentrated sulfuric acid (E) a one-molar solution of calcium chloride 48. How can you decide most easily whether a given gas is hydrogen or oxygen? (A) Determine its solubility in water. (B) Pass an electric spark through it. (C) Place a piece of glowing charcoal in the gas. (D) Determine its molar mass. (E) Smell the gas. 49. Which gas can be least readily readily collected by the displacement of water from the container? (A) H2 (B) N2 (C) O2 (D) NH3 (E) CO2 Metals & Non-Metals:







9 54. Which metal occurs in the earth's crust primarily as the free element? (A) gold (B) zinc (C) iron (D) aluminum Molecular Geometry: :O C N H 55. The molecule stars. The predicted C — N — H bond angle is about (A) 60° (B) 90° (C) 109° (D)

has been detected in gas clouds between 120° 120 °

56. The bond type and molecular polarity of SiCl4 are Bond Type (A) polar (B) polar (C) nonpolar (D) nonpolar

Polarity of Molecule nonpolar polar polar nonpolar

57. Which of these is a nonpolar molecule? H

(A)

F C

(C)

O

C

H

(B)

H

F

O H

(D)

58. Which molecule is nonpolar? (A) CCl4 (B) HCl

I

(C)

F C F

Br

CF3Cl (D)

59. Which molecule has the largest dipole moment? (A) CO2 (B) H2S (C) CCl4 (D)

CHCl3

(E)

NH3

H2O

Oxidation & Reduction:

60. Which process represents a general method for the p reparation of a metal from its compounds?







10 63. The action of hot, concentrated sulfuric acid on copper is best explained by the (A) acid property of the H3O+ ion. (B) oxidizing property of concentrated sulfuric acid. (C) oxidizing property of H3O+ ion. (D) dehydrating property of concentrated sulfuric acid. (E) volatility of concentrated sulfuric acid. 64. Under certain conditions H2O2 can act as an oxidizing agent; under other conditions, as a reducing agent. What is the best experimental evidence for this? (A)H2O2 is a good bleaching agent. (B)Peroxides are stronger oxidizing agents than are oxides. (C)H2O2 will decolorize KMnO4 solutions in the presence of an acid and will turn black lead sulfide to a white compound. (D)An atom within a compound can sometimes attain a more stable electronic structure either by gaining or by losing electrons. (E)The oxygen atoms in H2O2 share electrons; therefore, H2O2 is a covalent compound. Periodic Properties: 65. Which ion has the largest radius? 66. Which ion is the largest?

(A)

(A)

Te2 –

(B)

F –

(C)

Rb+

(D)

Ca2+

(B)

K +

(C)

Sc3+

(D)

S2 –

(C)

Fe3+, Fe2+

(D)

K 0, K +

67. Which pair is given in the order of increasing size? (A) Cl – , Cl0 (B) Sr, Ca

Mg2+

68. What happens when a bromine atom becomes a bromide ion? (A) A positive ion is formed. (B) The nucleus acquires a negative charge. (C) It becomes a particle with a smaller diameter. (D) It becomes a particle with a larger diameter. (E) Its atomic number is decreased by one. 69. The sizes of metal atoms (A) generally increase progressively from bottom to top in a group in the periodic table. (B) generally increase progressively from bottom in in the periodic table.







11 71. A 2.000 g sample of a Ni-Tl-Zn alloy is dissolved in nitric acid and 1.750 g of thallium(I) iodide, TlI, is precipitated by the addition of hydriodic h ydriodic acid. Calculate the percentage of thallium in the alloy. Molar Masses

(A)

Ni Tl Zn TlI 39.03%

58.71 g·mol – 1 204.4 g·mol – 1 65.37 g·mol – 1 331.3 g·mol – 1 (B) 53.98%

(C)

62.22%

(D)

87.50%

72. A piece of silver foil having a mass of 0.5840 g had become tarnished because of formation of Ag2S, with a mass increase of 0.0010 g. What percentage of the original silver has been converted to Ag2S? Atomic Molar Masses

(A)

S Ag 0.6%

32. g·mol – 1 108. g·mol – 1 (B) 1.2% (C)

1.8%

(D)

2.4%

73. What is the percentage of nitrogen by mass in (NH 4)3PO4? Atomic Molar Masses H N O P (A)

14/62  100%

1.0 g·mol – 1 14.0 g·mol – 1 16.0 g·mol – 1 31.0 g·mol – 1 (B)

21/80  100%

(C) 14/l13  100%

(D) 42/149  100%

74. A 2.00 g mixture of NaCl and NaNO3 dissolved in water required 90 mL of 0.10 M AgNO 3 to precipitate all the chloride. What is the mass percentage of NaCl in the original sample? sample? Atomic Molar Masses Na

23.0 g·mol – 1 g·mol 1









12 (A)

smaller.

(B)

the same.

(C)

larger.

(D)

unrelated.

77. When Al2O3(s) is formed from the elements at standard conditions, the values of  H 0 and G0 at 298 K are – 1617 1617 kJ·mol – 1 and – 1577 1577 kJ·mol – 1, respectively. The standard entropy of formation per mole, in joules per degree, will be (A) 315 (B) 157 (C) 93.3 (D) 0.0933 (E) +15.7 – 315 – 157 – 93.3 – 0.0933 78. Compound



SO2(g) SO3(g)

G

(kJ·mol – 1) 301 – 301 372 – 372

What is G0 for this reaction at 298 K? 2SO2(g) + O2(g) (A)

142 kJ – 142

(B)

200 kJ – 200

(C)

 2SO3(g)

744 kJ – 744

(D)

142 kJ

79. Consider ice in equilibrium with liquid water at 273 K. Which of the following relationships is correct for G(s), the free energy per mole of ice and G(l), the free energy per mole of the liquid? (A) G(s) is less than G(l) (B) G(s) is greater than G(l) (C) G(s) equals 0, G(l) equals 0 (D) G(s) equals G(l); neither equals 0 80. Which reaction is spontaneous in the direction written?

ACS PracticeTest 2

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