Nursing Elites

1. Which substance forms hydroxide ions when placed in water?

• A. Lemon juice
• B. Battery acid
• C. Vinegar
• D. Lye

Correct answer: D

Rationale: The correct answer is D, lye. Lye, also known as sodium hydroxide (NaOH), is a strong base that forms hydroxide ions (OH-) when placed in water. When lye dissolves in water, it dissociates into sodium ions (Na+) and hydroxide ions, making it an alkaline substance. Lemon juice, battery acid, and vinegar do not form hydroxide ions when placed in water. Lemon juice contains citric acid, battery acid contains sulfuric acid, and vinegar contains acetic acid, none of which produce hydroxide ions when dissolved in water.

2. How many pairs of electrons are shared between two atoms in a single bond?

• A. 1
• B. 2
• C. 3
• D. 4

Correct answer: A

Rationale: In a single bond, two atoms share one pair of electrons. This shared pair of electrons is what holds the atoms together in the bond. Therefore, the correct answer is A: 1. Choices B, C, and D are incorrect because they do not represent the number of electron pairs shared in a single bond.

3. What is the correct name of ZnSOâ‚„?

• A. Zinc sulfate
• B. Zinc sulfide
• C. Zinc sulfur
• D. Zinc oxide

Correct answer: A

Rationale: The correct name of ZnSO₄ is zinc sulfate. In this compound, zinc is combined with the polyatomic ion sulfate (SO₄). Sulfate is a common anion formed from sulfur and oxygen atoms. Therefore, the correct name for ZnSO₄ is zinc sulfate. Choice B, Zinc sulfide, is incorrect because sulfide is a different anion (S²⁻) compared to sulfate (SO₄²⁻). Choice C, Zinc sulfur, is incorrect as it does not represent the correct anion in the compound. Choice D, Zinc oxide, is incorrect as it involves an oxygen anion, not sulfate.

4. Which of the following factors would not affect rates of reaction?

• A. Temperature
• B. Surface area
• C. Pressure
• D. Time

Correct answer: D

Rationale: Time would not directly affect rates of reaction. The rate of a chemical reaction is determined by factors that affect the frequency of successful collisions between reactant molecules, leading to a reaction. Temperature, surface area, and pressure can influence reaction rates by impacting the kinetic energy of molecules, the exposed surface for collisions, and the concentration of reactants, respectively. However, time, in the context of this question, does not alter the rate of reaction but may affect the extent of the reaction or the amount of product formed over time.

5. Al(NO3)3 + H2SO4 → Al2(SO4)3 + HNO3 is an example of which kind of reaction?

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

Correct answer: C

Rationale: The given chemical equation represents a single replacement reaction. In this reaction, aluminum (Al) displaces hydrogen in sulfuric acid (H2SO4), forming aluminum sulfate (Al2(SO4)3) and releasing nitric acid (HNO3). Single replacement reactions involve an element replacing another element in a compound, which is evident in this reaction. Choice A, Decomposition reaction, is incorrect because decomposition reactions involve a single compound breaking down into two or more substances. Choice B, Synthesis reaction, is incorrect as it involves the combination of two or more substances to form a more complex compound. Choice D, Double replacement reaction, is also incorrect as it involves an exchange of ions between two compounds to form two new compounds.

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