Nursing Elites

1. Which of the following is the weakest intermolecular force?

• A. Dipole interactions
• B. Hydrogen bonding
• C. Van der Waals forces
• D. Dispersion forces

Correct answer: D

Rationale: Dispersion forces, also known as London dispersion forces, are the weakest intermolecular forces. They are temporary attractive forces that occur due to momentary shifts in electron distribution within molecules. While dipole interactions, hydrogen bonding, and Van der Waals forces are stronger intermolecular forces, dispersion forces are the weakest because they arise from short-lived fluctuations in electron density. Dipole interactions involve permanent dipoles in molecules, making them stronger than dispersion forces. Hydrogen bonding is stronger than dipole interactions and involves hydrogen atoms bonded to highly electronegative atoms. Van der Waals forces encompass dipole-dipole interactions and dispersion forces, making them stronger than dispersion forces alone.

2. What is the name of the bond formed when two atoms share electrons?

• A. Covalent bond
• B. Ionic bond
• C. Metallic bond
• D. Hydrogen bond

Correct answer: A

Rationale: A covalent bond is formed when two atoms share electrons, creating a stable electron configuration. This sharing allows both atoms to achieve a full outer shell of electrons, leading to a stable molecule. In contrast, an ionic bond involves the transfer of electrons from one atom to another, resulting in the formation of ions with opposite charges. Metallic bonds are formed between metal atoms and involve a 'sea of electrons' that are delocalized and free to move. Hydrogen bonds are a type of intermolecular force, not a true chemical bond, and occur between a hydrogen atom and a highly electronegative atom like oxygen or nitrogen.

3. Which factor does not affect the reaction rate of a chemical reaction?

• A. Temperature
• B. Surface area
• C. Concentration of reactants
• D. Color of the reactants

Correct answer: D

Rationale: The color of reactants is not a factor that affects the rate of a chemical reaction. Temperature, surface area, and concentration of reactants are known factors that influence the reaction rate. Temperature plays a significant role in altering the reaction rate by affecting the kinetic energy of molecules. Surface area impacts the rate by providing more area for collisions to occur. Concentration affects the frequency of effective collisions. On the other hand, the color of reactants is a physical property that does not directly affect the speed of a chemical reaction.

4. Identify the type of reaction shown: 8Fe + S → 8FeS

• A. Single displacement
• B. Double displacement
• C. Synthesis
• D. Acid-base

Correct answer: C

Rationale: The reaction shown (8Fe + S → 8FeS) is a synthesis reaction. In a synthesis reaction, two or more substances combine to form a single compound. In this case, iron (Fe) and sulfur (S) combine to form iron sulfide (FeS). The key characteristic of a synthesis reaction is the formation of a single product from multiple reactants, which aligns with the given chemical equation. Choice A, single displacement, involves an element displacing another in a compound, which is not the case here. Choice B, double displacement, involves the exchange of ions between two compounds, which is also not happening in this reaction. Choice D, acid-base, refers to reactions between an acid and a base to form salt and water, which is not the case in the given equation.

5. 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.

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