Chemistry Exam

1. Aluminum reacts with oxygen to form aluminum oxide. What is the coefficient of aluminum after balancing the reaction?

A. 4
B. 2
C. 8
D. 6

2. What property of an ionic compound can be investigated by heating it in a crucible?

A. Solubility
B. Melting point
C. Crystallization point
D. Malleability

3. Silver has two known isotopes, ¹⁰⁷Ag and ¹⁰⁸Ag with their percent abundance of 52% and 48%, respectively. What is the average atomic mass of silver?

A. 108.06
B. 107.89
C. 108.86
D. 107.48

4. Which reaction scheme below illustrates the formation of a cation?

A. 2Cl⁻ → Cl₂ + 2e⁻
B. Na → Na⁺ + e⁻
C. Mg²⁺ + 2e⁻ → Mg
D. S + 2e⁻ → S²⁻

5. Which of the following properties is the property of an acidic oxide? An acidic oxide reacts with

A. water to form acids.
B. salts to form acids.
C. basic oxides to form hydroxides and water.
D. bases to form basic hydroxide and water.

6. What is the name given to an acid that dissociates (ionizes) only to a slight extent in aqueous solution?

A. strong acid
B. dilute acid
C. concentrated acid
D. weak acid

7. Solutions can be classified based upon their pH values. What is a solution whose pH value 13?

A. Acidic solution
B. Amphoteric solution
C. Basic solution
D. Neutral solution

8. During laboratory class, a student placed clean water in a beaker and added pieces of calcium metal using tongs. After the reaction is completed, he/she tested the solution using red litmus paper. Which of the following will be observed?

A. The litmus paper turns to red.
B. The litmus paper turns to blue.
C. The litmus paper turns to colorless.
D. The litmus paper maintains its color.

9. The following reaction can be used for the synthesis of CH₃CH=CHCH₃ as a desired product.
CH₃CH₂CHBrCH₃ + CH₃S⁻ → CH₃CH=CHCH₃ + CH₃SH + Br⁻
Which of the following is the atom economy for the above reaction? (Atomic masses: H=1; C=12; S=32 and Br=80)

A. 48%
B. 30.43%
C. 80%
D. 56%

10. Which of the following process involves preventing the growth of bacteria, fungi and reducing the oxidation of fats?

A. Tanning
B. Haber-Bosch
C. Contact
D. Food preservation

11. Which of the following is the overall reaction for electrolysis of molten NaCl?

A. Na⁺(l) + Cl⁻(l) → Na(l) + ½Cl₂(g)
B. Na(l) + ½Cl₂(g) → Na⁺(l) + Cl⁻(l)
C. H₂O(g) → H₂(g) + ½O₂(g)
D. H₂(g) + ½O₂(g) → H₂O(g)

12. Which of the following occur during the electrolysis of dilute H₂SO₄?

A. the overall reaction is: H₂(g) + ½O₂(g) → H₂O(g)
B. SO₄²⁻ is discharged at the anode.
C. A basic solution is formed
D. H⁺ is discharged at the negative electrode

13. In an activity during laboratory session a small amount of lead bromide (PbBr₂) crystals were placed in a beaker. Two electrodes are inserted until they are in contact with the PbBr₂ crystals. When the PbBr₂ crystals in the beaker are gently heated, which of the following will be observed?

A. Bromide ion is oxidized at the cathode
B. Bromine gas is evolved at the anode
C. Lead (II) ion is oxidized at the cathode
D. Lead (II) ion is reduced at the anode

14. What is the name given to the pollution caused by the dumping of non-biodegradable wastes in to the environment?

A. land pollution
B. air pollution
C. water pollution
D. sound pollution

15. What is the purpose of the conversion of pig iron to steel?

A. To remove impurities by reduction
B. To remove impurities by oxidation
C. To decrease the concentration of iron in the pig iron
D. To increase the concentration of iron in the pig iron

16. Which of the following statements CORRECTLY describes the law of conservation of mass?

A. Mass is neither created nor destroyed during a chemical reaction.
B. The total mass of substances varies during a chemical reaction.
C. Pure compounds always contain the elements in the same percentage by mass.
D. A particular compound is composed of the same elements in the same parts by mass.

17. A mineral absorbs purple light of frequency 7.11 × 10¹⁴ Hz. What is the wavelength (in nm) of the absorbed light? (C = 3.00 × 10⁸ m/s)

A. 237.5 nm
B. 184.4 nm
C. 514.5 nm
D. 421.9 nm

18. Why do atoms absorb energy when their electrons undergo transitions from a lower energy to a higher energy level? This is because

A. the electrons of the atoms move from one orbit of higher radius to another one having lower radius.
B. the electrons of the atoms move from one orbit of lower radius to another one having larger radius.
C. electrons of the atoms absorb energy when they go from higher to lower energy.
D. the electrons of the atoms do not have allowable energy levels.

19. What are the quantum numbers for the 5s orbital?

A. n = 5; l = 1; m_l = −2; m_s = ±½
B. n = 5; l = 0; m_l = −1; m_s = ±½
C. n = 5; l = 0; m_l = 0; m_s = ±½
D. n = 5; l = 2; m_l = −2; m_s = ±½

20. Which of the following is CORRECT about the set of quantum numbers assigned to the two electrons of the helium atom?

A. The second electron occupies the same orbital as the first with the same spin quantum number.
B. Both electrons have the same four quantum numbers.
C. The magnetic quantum numbers of both electrons are different.
D. The second electron occupies the same orbital as the first with the opposite spin quantum number.

Chemistry Exam: Part 1

Exam Results