Nursing Elites

1. What is the stoichiometric coefficient of nitrogen (N2) in the balanced equation for the Haber process: N2 + 3H2 → 2NH3?

• A. 1
• B. 2
• C. 3
• D. 4

Correct answer: a

Rationale: The coefficient of N2 is 1 in the balanced equation

2. Which structure in the heart is responsible for preventing the backflow of blood from the left ventricle into the left atrium?

• A. Aortic valve
• B. Pulmonary valve
• C. Tricuspid valve
• D. Mitral valve

Correct answer: D

Rationale: The correct answer is D, the Mitral valve. The Mitral valve, also known as the bicuspid valve, is located between the left atrium and left ventricle in the heart. It consists of two cusps that close tightly when the left ventricle contracts, preventing the backflow of blood into the left atrium. The aortic valve (option A) is responsible for preventing the backflow of blood from the aorta into the left ventricle, not the left atrium. The pulmonary valve (option B) prevents backflow from the pulmonary artery into the right ventricle, and the tricuspid valve (option C) prevents backflow from the right ventricle into the right atrium. Therefore, the Mitral valve is specifically responsible for preventing backflow from the left ventricle into the left atrium.

3. Which of the following is NOT a property of a catalyst?

• A. Increases the rate of a reaction
• B. Remains unchanged after the reaction
• C. Lowers the activation energy
• D. Creates new products

Correct answer: D

Rationale: A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process. It remains unchanged after the reaction, which eliminates option B. A catalyst works by lowering the activation energy required for the reaction to occur, which eliminates option C. A catalyst does not create new products in a reaction; it only facilitates the conversion of reactants into products more efficiently. Therefore, option D is NOT a property of a catalyst.

4. The number of protons in an atom determines its:

• A. Mass number
• B. Atomic number
• C. Atomic number
• D. Valence electron count

Correct answer: B

Rationale: The atomic number (Z) equals the number of protons and defines an element's core identity.

5. Centrioles are structures involved in cell division. What is their specific role?

• A. Forming the nuclear envelope
• B. Replicating DNA
• C. Organizing microtubules during cell division
• D. Protein synthesis

Correct answer: C

Rationale: Centrioles are cylindrical structures found in animal cells that play a crucial role in organizing microtubules during cell division. They form the spindle fibers that help separate chromosomes during mitosis and meiosis. This organization is essential for the proper alignment and separation of chromosomes, ensuring accurate distribution of genetic material to daughter cells. Centrioles do not participate in forming the nuclear envelope, replicating DNA, or protein synthesis. Therefore, the correct answer is C, as centrioles are primarily involved in microtubule organization to facilitate cell division.

6. The energy absorbed during a chemical reaction is called:

• A. Kinetic energy
• B. Potential energy
• C. Heat energy
• D. Endothermic energy

Correct answer: D

Rationale: Endothermic means "inward heat," indicating energy is absorbed during the reaction.

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