columns of the periodic table are called

HESI A2

Chemistry HESI A2 Quizlet

1. What are the columns of the periodic table called?

A. Periods
B. Families
C. Groups
D. Rows

Correct answer: C

Rationale: In the periodic table, columns are referred to as groups, not periods, families, or rows. These groups share similar chemical properties due to the arrangement of elements within each group, which is based on the number of valence electrons. The vertical columns help classify elements with similar characteristics. Periods refer to the rows of the periodic table, while families or groups are the vertical columns.

2. When balanced, the reaction Fe + Oâ‚‚ â†’ FeO will be?

A. 2Fe + 2Oâ‚‚ â†’ 3FeO
B. 4Fe + 6Oâ‚‚ â†’ 6FeO
C. 2Fe + 3Oâ‚‚ â†’ 2FeO
D. 4Fe + 3Oâ‚‚ â†’ 2FeO

Correct answer: C

Rationale: To balance the chemical equation Fe + Oâ‚‚ â†’ FeO, the coefficients needed are 2 for Fe and 1 for O. Therefore, the balanced equation becomes 2Fe + Oâ‚‚ â†’ 2FeO, which translates into 2Fe + 3Oâ‚‚ â†’ 2FeO. This corresponds to option C. Choice A has the incorrect number of oxygen molecules. Choice B has an incorrect number of Fe atoms on the product side. Choice D also has an incorrect number of Fe atoms on the product side.

3. How many electrons are shared in a single covalent bond?

A. 1
B. 2
C. 3
D. 4

Correct answer: B

Rationale: The correct answer is B: '2'. In a single covalent bond, two electrons are shared between two atoms. Each atom contributes one electron to form the bond, resulting in the sharing of a total of two electrons. Choice A is incorrect because a single covalent bond involves the sharing of two electrons, not one. Choices C and D are incorrect as they do not represent the correct number of electrons shared in a single covalent bond.

4. To the nearest whole number, what is the mass of one mole of water?

A. 16 g/mol
B. 18 g/mol
C. 20 g/mol
D. 22 g/mol

Correct answer: B

Rationale: The molar mass of water (Hâ‚‚O) is calculated by adding the atomic masses of two hydrogen atoms (each with a molar mass of approximately 1 g/mol) and one oxygen atom (with a molar mass of approximately 16 g/mol). Therefore, the molar mass of water is approximately 18 g/mol, making choice B the correct answer. Choice A (16 g/mol) is incorrect because it represents the molar mass of oxygen, not water. Choices C (20 g/mol) and D (22 g/mol) are incorrect as they do not correspond to the molar mass of water.

5. Which material has the smallest specific heat capacity?

A. water
B. wood
C. aluminum
D. glass

Correct answer: C

Rationale: Specific heat capacity is the amount of heat required to raise the temperature of a unit mass of a substance by one degree Celsius. Among the options provided, aluminum has the smallest specific heat capacity. This means that it requires the least amount of heat to raise its temperature compared to water, wood, and glass. Water has a high specific heat capacity, making it resistant to temperature changes, while wood and glass have higher specific heat capacities compared to aluminum.