Nursing Elites

1. The chemical equation below is unbalanced. When it is properly balanced, how many molecules of carbon dioxide (CO2) are produced for each molecule of propane (C3H8) in the reaction? 3C3H8 + 5O2 → 3CO2 + 4H2O

• A. One Half.
• B. Two.
• C. Three.
• D. Five.

Correct answer: B

Rationale: The balanced chemical equation for the combustion of propane is: 3C3H8 + 5O2 → 3CO2 + 4H2O. This equation shows that for every 3 molecules of propane (C3H8) consumed, 3 molecules of carbon dioxide (CO2) are produced. Therefore, when properly balanced, 3CO2 are produced for each molecule of propane used. Thus, the correct answer is B: Two. Choices A, C, and D are incorrect because they do not reflect the correct stoichiometry as determined by the balanced equation.

2. Which structure in the heart is responsible for pumping oxygenated blood to the body?

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

Correct answer: B

Rationale: The left ventricle is the chamber responsible for pumping oxygenated blood from the heart to the body. It receives oxygen-rich blood from the left atrium and contracts to push this blood out to the rest of the body through the aorta. The right ventricle pumps deoxygenated blood to the lungs for oxygenation, making choices A, C, and D incorrect for this function. Therefore, the correct answer is B, the Left ventricle.

3. Two identical balls, one made of clay and the other made of steel, are dropped from the same height. Which ball reaches the ground first, neglecting air resistance?

• A. The clay ball due to its lower density
• B. The steel ball due to its higher density
• C. Both balls reach the ground simultaneously
• D. It depends on the initial velocities of the balls

Correct answer: C

Rationale: In the absence of air resistance, both balls will experience the same acceleration due to gravity (9.8 m/s^2) regardless of their densities or materials. This means that both balls will reach the ground at the same time, assuming they are dropped from the same height simultaneously. The differences in density or material composition do not affect the rate at which objects fall in a vacuum. Therefore, both the clay and steel balls, being identical in shape and starting position, will have the same free-fall acceleration and will hit the ground simultaneously. Choices A and B are incorrect because the density of the materials does not impact the time it takes for objects to fall under gravity alone. Choice D is incorrect as the initial velocities do not play a role in the time taken to fall in a vacuum, where only the acceleration due to gravity affects the motion.

4. Which level of protein structure is defined by the folds and coils of the protein's polypeptide backbone?

• A. Primary
• B. Secondary
• C. Tertiary
• D. Quaternary

Correct answer: B

Rationale: The correct answer is B: Secondary. The secondary structure of a protein is defined by the folding and coiling of the polypeptide backbone into structures like alpha helices and beta sheets. Secondary structure primarily involves interactions such as hydrogen bonding within the backbone. This level of protein structure is distinct from primary structure (A) which refers to the linear sequence of amino acids, tertiary structure (C) which involves the overall 3D arrangement of a single polypeptide chain, and quaternary structure (D) which pertains to the interaction between multiple polypeptide chains in a protein complex.

5. Which law of motion explains the behavior of rockets in space?

• A. Newton's First Law
• B. Newton's Second Law
• C. Newton's Third Law
• D. None of the above

Correct answer: C

Rationale: The correct answer is Newton's Third Law. Newton's Third Law states that for every action, there is an equal and opposite reaction. In the case of rockets in space, the action is the expulsion of gas from the rocket engines, and the reaction is the forward motion of the rocket. This law explains how rockets are able to propel themselves forward in the vacuum of space. Choices A and B are incorrect because Newton's First Law (inertia) and Second Law (F=ma) do not directly explain the behavior of rockets in space. Choice D is incorrect as Newton's Third Law specifically addresses the principle behind rockets' motion in space.

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