Nursing Elites

1. Which elements are typically involved in hydrogen bonding?

• A. Carbon, hydrogen, oxygen
• B. Fluorine, chlorine, oxygen
• C. Fluorine, chlorine, nitrogen
• D. Fluorine, oxygen, nitrogen

Correct answer: D

Rationale: Hydrogen bonding occurs between hydrogen and highly electronegative atoms such as fluorine, oxygen, and nitrogen. These atoms have a strong pull on the shared electrons, leading to a partial negative charge on them, which allows them to form hydrogen bonds with hydrogen or other electronegative atoms. Choice A is incorrect because carbon is not typically involved in hydrogen bonding. Choice B is incorrect because chlorine is not as electronegative as nitrogen, and choice C is incorrect because nitrogen is more electronegative than chlorine.

2. What is the pH of acids?

• A. 7.5
• B. < 7
• C. > 7
• D. 7

Correct answer: B

Rationale: The correct answer is B: < 7. Acids have a pH lower than 7, indicating higher acidity. A pH below 7 signifies an acidic solution, with lower values indicating stronger acids. Choice A (7.5) is incorrect as it is greater than 7, which is alkaline. Choice C (> 7) is incorrect as values greater than 7 represent alkaline/basic solutions. Choice D (7) is incorrect because a pH of 7 is neutral, not acidic.

3. Which type of chemical reaction involves two ionic compounds where the reactants yield 'switched partners'?

• A. Single replacement
• B. Double replacement
• C. Synthesis
• D. Decomposition

Correct answer: B

Rationale: The correct answer is 'Double replacement.' In a double replacement reaction, two ionic compounds react by exchanging ions, resulting in the formation of two new compounds where the positive and negative ions have 'switched partners.' This type of reaction is characterized by the exchange of ions between the reactants. Choice A, 'Single replacement,' involves an element replacing another in a compound, not the exchange of partners like in the given scenario. Choice C, 'Synthesis,' is the combination of two or more substances to form a more complex product, not involving the exchange of partners. Choice D, 'Decomposition,' is the breakdown of a compound into simpler substances, which is different from the scenario described in the question.

4. What charge do Group VIIA elements have?

• A. -1
• B. -2
• C. 0
• D. 1

Correct answer: A

Rationale: Group VIIA elements, also known as halogens, have a tendency to gain one electron to achieve a stable electron configuration, resulting in a -1 charge. This is because they have seven valence electrons and need one more to complete their octet, making them highly reactive in forming -1 ions. Therefore, the correct answer is A. Choice B (-2) is incorrect because Group VIIA elements typically gain one electron, not two. Choice C (0) is incorrect as these elements tend to form -1 ions by gaining one electron. Choice D (1) is incorrect because Group VIIA elements gain electrons to form negative ions, not positive ones.

5. Where would you expect tap water to fall on the pH scale?

• A. Between 1 and 3
• B. Between 4 and 6
• C. Between 6 and 8
• D. Between 8 and 10

Correct answer: C

Rationale: Tap water typically falls within the pH range of 6 to 8, making it slightly acidic to neutral. Most municipal water systems aim to provide water that is safe for consumption and falls within this pH range. A pH level of 7 is considered neutral, so tap water may vary slightly on either side of this number but typically remains within the 6 to 8 range to ensure it is safe for consumption. Choices A, B, and D are incorrect because tap water is not expected to have a pH as low as 1-3 (highly acidic) or as high as 8-10 (alkaline); it usually falls within the slightly acidic to neutral range, hence falling between 6 and 8 on the pH scale.

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