Nursing Elites

1. Which of the following properties is NOT characteristic of a covalent bond?

• A. Sharing of electrons between atoms
• B. High melting and boiling points
• C. Low electrical conductivity in solid state
• D. Directional bonding

Correct answer: B

Rationale: Covalent bonds are formed by the sharing of electrons between atoms, leading to the formation of molecules with directional bonding. This means that the atoms are held together in a specific orientation. Covalent compounds generally exhibit low melting and boiling points compared to ionic compounds due to the weaker intermolecular forces present in covalent compounds. Furthermore, covalent compounds do not conduct electricity in the solid state because the electrons are localized between the atoms and are not free to move and carry charge. Hence, high melting and boiling points are not characteristic of covalent bonds. The correct answer is 'B' because high melting and boiling points are typically associated with ionic compounds due to their strong electrostatic interactions, while covalent compounds have lower melting and boiling points. Choices A, C, and D are all characteristics of covalent bonds, making them incorrect answers for this question.

2. Margery is planning a vacation, and her round-trip airfare will cost $572. Her hotel costs $89 per night, and she will be staying at the hotel for five nights. She has allotted a total of $150 for sightseeing and expects to spend about $250 on meals. She will receive a 10% discount on the hotel price after the first night. What is the total amount Margery expects to spend on her vacation?

• A. $1,328.35
• B. $1,373.50
• C. $1,381.40
• D. $1,417.60

Correct answer: C

Rationale: To calculate Margery's total expenses: Airfare ($572) + Hotel ($89 * 5 nights) = $572 + $445 = $1017. After the first night's stay, Margery receives a 10% discount on the remaining four nights, making the total hotel cost $445 - (10% of $89) = $445 - $8.90 = $436.10. Adding sightseeing ($150) and meals ($250) to the total gives $1017 + $150 + $250 = $1417. Margery's expected expenses are $1417, not $1381.40 as stated in the original rationale. Therefore, the correct answer is $1,417.60 (Option D).

3. This chart indicates the number of sales of CDs, vinyl records, and MP3 downloads that occurred over the last year. Approximately what percentage of the total sales was from CDs?

• A. 55%
• B. 25%
• C. 40%
• D. 5%

Correct answer: C

Rationale: To determine the percentage of CD sales out of the total sales, we need to consider the total sales of CDs, vinyl records, and MP3 downloads. To find the percentage of CD sales, we divide the total sales of CDs by the sum of total sales of CDs, vinyl records, and MP3 downloads, and then multiply by 100. In this case, the correct calculation shows that CDs accounted for 40% of the total sales. Choice A (55%) is incorrect as it overestimates the contribution of CDs. Choice B (25%) is incorrect as it underestimates the percentage of CD sales. Choice D (5%) is also incorrect as it severely underestimates the share of CD sales in the total sales.

4. An atom has 17 protons, 20 neutrons, and 17 electrons. What is its mass, in amu?

• A. 17
• B. 20
• C. 37
• D. 54

Correct answer: C

Rationale: The atomic mass of an atom is the sum of the protons and neutrons in its nucleus. In this case, the atom has 17 protons and 20 neutrons, totaling 37 particles in the nucleus. Electrons are not considered in the atomic mass calculation as their mass is negligible compared to protons and neutrons. Therefore, the mass of the atom in atomic mass units (amu) is 37.

5. Which molecules are soluble in nonpolar solvents but are hydrophobic?

• A. Carbohydrates
• B. Lipids
• C. Proteins
• D. Nucleic acids

Correct answer: B

Rationale: Lipids are hydrophobic molecules that are soluble in nonpolar solvents like oils but insoluble in water. They consist of fats, oils, waxes, and steroids and play essential roles in energy storage, insulation, and cell membrane structure. Carbohydrates, proteins, and nucleic acids are not typically soluble in nonpolar solvents and do not exhibit the same hydrophobic characteristics as lipids. Carbohydrates are usually hydrophilic and soluble in water, proteins have both hydrophilic and hydrophobic regions but are not generally soluble in nonpolar solvents, and nucleic acids are polar molecules that are not known for their solubility in nonpolar solvents.

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