Nursing Elites

1. What is the net ionic equation for the reaction: 2HCl(aq) + Ba(OH)2(aq) → 2H2O(l) + BaCl2(aq)?

• A. 2H+(aq) + 2OH-(aq) → 2H2O(l)
• B. 2HCl(aq) + Ba(OH)2(aq) → BaCl2(aq) + 2H2O(l)
• C. 2H+(aq) + Ba2+(aq) → Ba2+(aq) + 2H+(aq)
• D. Ba(OH)2(aq) + HCl(aq) → BaCl2(aq) + 2H2O(l)

Correct answer: A

Rationale: In the given reaction, the complete ionic equation is: 2H+(aq) + 2Cl-(aq) + Ba2+(aq) + 2OH-(aq) → 2H2O(l) + Ba2+(aq) + 2Cl-(aq). Spectator ions (Ba2+ and Cl-) do not participate in the net ionic equation, which simplifies to: 2H+(aq) + 2OH-(aq) → 2H2O(l). This equation represents the significant species involved in the reaction, showcasing the formation of water from the combination of hydrogen ions and hydroxide ions, resulting in the production of water molecules.

2. Which element is essential for the formation of hemoglobin?

• A. Calcium
• B. Iron
• C. Potassium
• D. Sodium

Correct answer: B

Rationale: The correct answer is Iron. Iron is essential for the formation of hemoglobin, the protein in red blood cells that binds and transports oxygen throughout the body. Calcium (Choice A), Potassium (Choice C), and Sodium (Choice D) are not directly involved in the formation of hemoglobin and its oxygen-carrying function.

3. Which property of matter measures the amount of space occupied by an object?

• A. Mass
• B. Density
• C. Weight
• D. Volume

Correct answer: D

Rationale: Volume is the property of matter that measures the amount of space occupied by an object. Mass refers to the amount of matter in an object, weight is the force of gravity acting on an object, and density is the mass of an object per unit volume. Volume specifically quantifies the space occupied by an object, making it the correct answer in this context.

4. What is the oxidation state of carbon in CH4?

• A. +1
• B. -1
• C. +2
• D. -4

Correct answer: D

Rationale: In CH4 (methane), carbon is bonded to four hydrogen atoms. Hydrogen has an oxidation state of +1. Since the overall charge of CH4 is 0, the oxidation state of carbon must be -4 to balance the charges. Each hydrogen contributes an oxidation state of +1, resulting in a total of +4 from hydrogen atoms. To achieve a total oxidation state of 0 for the molecule, carbon must have an oxidation state of -4 to offset the contribution from hydrogen. Therefore, the correct answer is -4. Choices A, B, and C are incorrect: +1 is the oxidation state of hydrogen, -1 is not the oxidation state of carbon in methane, and +2 is not the correct oxidation state of carbon in CH4.

5. What is the term for the ability of a substance to dissolve in another substance?

• A. Solubility
• B. Miscibility
• C. Immiscibility
• D. Reactivity

Correct answer: A

Rationale: Solubility is the property that describes the ability of a substance to dissolve in another substance. When a substance is soluble in another, it means it can form a homogeneous solution by dispersing at a molecular level within the solvent. Miscibility, on the other hand, refers to the ability of two liquids to mix and form a homogeneous solution. Immiscibility indicates the inability of substances to mix to form a homogeneous solution. Reactivity pertains to the ability of a substance to undergo chemical reactions, which is distinct from the concept of solubility.

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