Nursing Elites

1. What is the balanced chemical equation for the reaction between sodium and chlorine to form sodium chloride?

• A. Na + Cl2 -> NaCl
• B. 2Na + Cl2 -> 2NaCl
• C. Na2 + Cl -> 2NaCl
• D. Na + 2Cl -> NaCl2

Correct answer: B

Rationale: In a balanced chemical equation, the number of atoms of each element must be the same on both sides of the equation. When sodium (Na) reacts with chlorine (Cl2) to form sodium chloride (NaCl), we need to ensure the equation is balanced. There are 2 chlorine atoms in Cl2; hence, we need 2 sodium atoms on the left side to balance it. Therefore, the balanced chemical equation is 2Na + Cl2 -> 2NaCl. Choice A is incorrect because it does not have the correct coefficients to balance the equation. Choice C is incorrect as it incorrectly represents the formula of sodium. Choice D is incorrect as it forms NaCl2, which is not the correct compound formed in this reaction.

2. Which of the following is a representation of a natural pattern or occurrence that is difficult or impossible to experience directly?

• A. A theory
• B. A model
• C. A law
• D. An observation

Correct answer: B

Rationale: A model is a representation used by scientists to understand and explain natural phenomena that are challenging or impossible to observe directly. Models help visualize complex systems or processes that are not easily accessible for direct observation. The other choices are incorrect because: A) A theory is an explanation or interpretation of observable facts or phenomena. C) A law describes a consistent and universal phenomenon or relationship in nature based on repeated observations. D) An observation is a direct act of watching or taking note of a phenomenon or behavior.

3. What is the pH of a solution with a hydrogen ion concentration of (1x10^{-9}) M?

• A. 5
• B. 7
• C. 9
• D. 11

Correct answer: C

Rationale: The pH of a solution can be calculated using the formula: pH = -log[H+]. Given that the hydrogen ion concentration is \(1 \times 10^{-9}\) M, the pH can be calculated as pH = -log(1 x 10^-9) = 9. Therefore, the correct answer is C) 9.

4. Which chamber of the heart is the largest?

• A. Right atrium
• B. Left atrium
• C. Right ventricle
• D. Left ventricle

Correct answer: D

Rationale: The correct answer is D, the left ventricle. The left ventricle is the largest and strongest chamber of the heart. It is responsible for pumping oxygenated blood to the entire body through the aorta, playing a crucial role in the circulatory system. Choices A, B, and C are incorrect. The right atrium receives deoxygenated blood from the body, the left atrium receives oxygenated blood from the lungs, and the right ventricle pumps deoxygenated blood to the lungs for oxygenation. However, the left ventricle is the largest chamber and performs the vital function of pumping oxygen-rich blood to the body.

5. Which of the following is a strong base commonly used in cleaning products?

• A. Sodium hydroxide (NaOH)
• B. Ammonium hydroxide (NH₄OH)
• C. Calcium hydroxide (Ca(OH)₂)
• D. Potassium hydroxide (KOH)

Correct answer: A

Rationale: Sodium hydroxide (NaOH) is a strong base commonly used in cleaning products due to its effectiveness in breaking down grease and fats. It is known for its corrosive properties and is commonly found in drain cleaners and oven cleaners. While ammonium hydroxide, calcium hydroxide, and potassium hydroxide are also bases, they are not as strong as sodium hydroxide and are not as commonly used in cleaning products. Ammonium hydroxide is more commonly found in household cleaning products for its disinfectant properties, calcium hydroxide is used in agriculture and construction, and potassium hydroxide is often used in industries like soap manufacturing and biodiesel production.

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