Chemistry Exam

61. Which one of the following CORRECTLY shows the relative charges of an electron, proton and neutron, respectively?

A. -1, +1, 0
B. -1, 0, +1
C. 0, +1, -1
D. 0, -1, +1

62. Which statement below CORRECTLY describes the Bohr's model of an atom?

A. Protons move in circular orbits around the nucleus.
B. Electrons move in circular orbits around the nucleus.
C. Protons and electrons are found in the nucleus.
D. Electrons and neutrons are found in the nucleus.

63. Which statement below CORRECTLY describes periodicity? Periodicity is

A. a measure of electronegativity which runs from least electronegative to most electronegative elements.
B. a column of the Periodic Table which contains elements with similar chemical properties.
C. a regular repetition of chemical and physical properties in the Periodic Table.
D. a row in the Periodic Table which contains elements with same number of shells.

64. Which statement below CORRECTLY expresses hydrogen bonding? It is formed by bonding

A. two hydrogen atoms with equal sharing of electrons.
B. two hydrogen atoms with unequal sharing of electrons
C. a hydrogen atom to an element such as sodium.
D. a hydrogen atom to an element such as oxygen.

65. For the dissociation of HNO₂:
HNO₂(aq) ⇌ NO₂^- (aq) + H⁺(aq). What is the percent ionization of a 0.5M solution of HNO₂?
(Ka of HNO₂ = 7.1 x 10^-4)

A. 3.8%
B. 9.1$
C. 0.2%
D. 1.9%

66. What is the base(K_b) dissociation constant 0.47M solution of a weak base whose pOH is 2?

A. 4.0 x 10^-4
B. 4.7 x 10^-4
C. 2.17 x 10^-4
D. 0.47 x 10^-4

67. The cell notation Zn(s)|Zn²⁺aq helf-cell and another helf-cell containing copper immersed in 1.00 M CuSO₄. When the Zn was conected as the anode at 25^oC the cell potentialreading on the voltmeter shows 1.1 V. which of the following is Not correct regarding the cell potential measurement ?

A. Zinc electrod was dissolves and The blue into blue color of CuSO₄ solution fades.
B. Electrons travel through the external circuit from copper cathode to the zinc anode.
C. The mass of the copper rod increases as the reaction proceeds.
D. The salt bridge completes the circuit by permitting ions to migrate from one cell to the other.

68. Which of the following polymer structures represent polypropylene?

A.

   H  H      |
   |  |      |
  C — C      |
   |  |      |
   H  CH3    |n
                        

B.

    H   H      |
    |   |      |
  C — — C      |
    |   |      |
    H   COOCH3 |n
                        

C.

   H   H    |
   |   |    | 
   C — C    |    
   |   |    |
   H   H    |n
                        

D.

     H   H    |
     |   |    |
     C — C    |
     |   |    |
    Cl   H    |n
                        

69. Which one of the following statements CORRECTLY describes the relationship among wavelength , frequency , and speed of electromagnetic wave?

A. As the wavelength decreases, the speed of the wave decreases.
B. As the frequency decreases, the speed of the wave increases.
C. As the wavelength decreases, the frequency increases.
D. As the frequency increases, the wavelength increases.

70. Which one of the following organic compounds has the highest boiling point?

A. Ethanol
B. Ethene
C. Ethane
D. Ethanal

71. Which one of the following terms is CORRECTLY paired with its definition?

A. Lewis acid: electron pair acceptor
B. Lewis base: electron pair donor
C. Brønsted–Lowry base: proton donor
D. Brønsted–Lowry acid: proton acceptor

72. Given the following information:

CH₃COOH (aq) ⇌ CH₃COO^- (aq) + H⁺ (aq)

Initial concentration (mol/L)    0.2     0     0
Change                           -x      +x    +x
Equilibrium concentration       0.2 − x   x     x

Which of the following expressions represent the percent ionization of CH₃COOH?

A. ((0.2 - x) / 0.2 )· 100%
B. (x / (0.2 - x)) · 100%
C. ((0.2 - x) / x) · 100%
D. (x / 0.2) · 100%

73. Which one of the following is an assumption in the kinetic theory of gases?

A. Gas molecules are in fixed position with negligible attraction.
B. Gas molecules attract each other and are in continuous motion.
C. The total kinetic energy of gas molecules is conserved during collision.
D. Gas molecules are in random motion with no interactions.

74. The rate of diffusion of an unknown gas is 0.5 times the rate of diffusion of helium gas. What is the molar mass of the unknown gas? (Atomic mass He = 4.0 g/mole)

A. 16.0 g/mole
B. 32.0 g/mole
C. 2.0 g/mole
D. 8.0 g/mole

75. A student added boiling chips into a beaker of water while carrying out an activity to determine the boiling point of water. Why do you think the boiling chips are necessary?

A. To maintain constant temperature and pressure
B. To reach the boiling point with less consumption of heat
C. To ensure smooth rate of evaporation
D. To speed up the rate of evaporation

76. What is the oxidation number of manganese in KMnO₄?

A. +4
B. +7
C. +5
D. +6

77. In which of the following components of the environment does photosynthesis take place?

A. Lithosphere
B. Biosphere
C. Atmosphere
D. Hydrosphere

78. Which of the following is NOT true about greenhouse effect and greenhouse gases?

A. Oxygen O₂ and nitrogen N₂ are transparent to infrared radiation.
B. The greater the percentage of greenhouse gases in the atmosphere, the greater the warming of the earth should be.
C. Greenhouse effect is due to trapping of the infrared radiation by certain gases in the atmosphere.
D. Carbon dioxide and water vapor are greenhouse gases.

79. In which of the following is the type of natural resource and the given example CORRECTLY paired?

A. Non-renewable resources; animal wool
B. Renewable resources; water
C. Non-renewable resources; copper
D. Renewable resources; crops

80. Which of the following compounds is a Brønsted–Lowry base?

A. HCl
B. H₂S
C. NH₃
D. BF₃

Chemistry Exam: Part 4

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