Nursing Elites

1. Among the following elements, which is a nonmetal?

• A. Mercury
• B. Magnesium
• C. Sulfur
• D. Potassium

Correct answer: C

Rationale: Sulfur is a nonmetal as it is located on the right side of the periodic table. Nonmetals generally exhibit properties such as being brittle, poor conductors of heat and electricity, and having lower melting points compared to metals. Mercury (A), Magnesium (B), and Potassium (D) are all metals due to their metallic properties. Mercury is a liquid metal at room temperature, Magnesium is a solid metal, and Potassium is a solid metal as well. Therefore, the correct answer is C, Sulfur.

2. A salt solution has a molarity of 5 M. How many moles of this salt are present in 0 L of this solution?

• A. 0
• B. 1.5
• C. 2
• D. 3

Correct answer: A

Rationale: Molarity is defined as the number of moles of solute per liter of solution. A molarity of 5 M indicates there are 5 moles of salt in 1 liter of the solution. Since the volume of the solution is 0 liters, multiplying the molarity by 0 liters results in 0 moles of salt (5 moles/L x 0 L = 0 moles). Therefore, the correct answer is 0. Option B, 1.5, is incorrect because it doesn't consider the volume being 0 liters. Options C and D, 2 and 3 respectively, are also incorrect as they do not account for the zero volume of the solution. Hence, there are no moles of salt present in 0 liters of the solution.

3. Which of these represents a strong acid?

• A. CH₃COOH
• B. H₂SO₄
• C. NH₃
• D. KOH

Correct answer: B

Rationale: Among the options provided, H₂SO₄ (sulfuric acid) represents a strong acid. Strong acids completely ionize in water to produce a high concentration of H+ ions. Sulfuric acid is a strong acid known for its ability to dissociate almost completely in water, making it a strong acid. Choice A, CH₃COOH (acetic acid), is a weak acid that only partially dissociates in water. Choices C and D, NH₃ (ammonia) and KOH (potassium hydroxide), are bases and not acids.

4. 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.

5. What type of chemical reaction is represented by AB → A + B?

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

Correct answer: B

Rationale: The chemical equation AB → A + B represents a decomposition reaction. In a decomposition reaction, a single compound breaks down into two or more simpler substances. In this specific reaction, compound AB is decomposed into its elements, A and B, making it a decomposition reaction. Choice A, Synthesis, involves the combination of two or more substances to form a more complex product, which is not the case here. Choices C and D, Single replacement and Double replacement, involve the exchange of ions between compounds or elements, which is not happening in the given reaction.

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