Nursing Elites

1. How does the Law of Conservation of Mass apply to this reaction: 2H₂ + O₂ → 2H₂O?

• A. Electrons are not lost.
• B. The hydrogen does not lose mass.
• C. New water molecules are formed.
• D. There is no decrease or increase in matter.

Correct answer: D

Rationale: The Law of Conservation of Mass states that matter cannot be created or destroyed in a chemical reaction. In the given reaction, 2 moles of hydrogen combine with 1 mole of oxygen to form 2 moles of water. The total mass of the reactants (hydrogen and oxygen) is equal to the total mass of the products (water), meaning there is no decrease or increase in matter. The total mass of the system remains constant, demonstrating the conservation of mass. Choices A, B, and C are incorrect because the conservation of mass does not specifically relate to electrons, individual elements (like hydrogen), or the formation of new molecules; instead, it focuses on the overall mass of the system before and after the reaction.

2. A car travels 60 miles in 1 hour. How long will it take to travel 180 miles at the same speed?

• A. 3 hours
• B. 4 hours
• C. 2.5 hours
• D. 5 hours

Correct answer: A

Rationale: To find the time needed to travel 180 miles at the same speed of 60 miles per hour, you divide the total distance by the speed. 180 miles ÷ 60 mph = 3 hours. Therefore, it will take 3 hours to travel 180 miles at the given speed. Choice B, 4 hours, is incorrect as it does not align with the calculation. Choice C, 2.5 hours, is incorrect as it underestimates the time needed for the distance. Choice D, 5 hours, is incorrect as it overestimates the time required based on the given speed.

3. Which of the following organs is responsible for the mechanical breakdown of food into smaller pieces?

• A. Esophagus
• B. Stomach
• C. Small intestine
• D. Mouth

Correct answer: D

Rationale: The correct answer is D: Mouth. The mouth is responsible for the mechanical breakdown of food through chewing and mixing with saliva. This process is essential for breaking down food into smaller, more digestible pieces before swallowing. The esophagus (choice A) is a muscular tube that transports food from the mouth to the stomach and does not participate in the mechanical breakdown of food. The stomach (choice B) primarily functions to further break down food using acids and enzymes, rather than mechanical means. The small intestine (choice C) is responsible for absorbing nutrients from the digested food, not for the mechanical breakdown of food.

4. What is the area of the largest circle that can fit entirely inside a rectangle that measures 8 centimeters by 10 centimeters?

• A. 18Ï€ cm²
• B. 10Ï€ cm²
• C. 16Ï€ cm²
• D. 8Ï€ cm²

Correct answer: C

Rationale: The largest circle that can fit inside the rectangle would have a diameter of 8 cm, which means the radius is half of the diameter, thus 4 cm. The area of a circle is calculated using the formula A = πr², where r is the radius. Substituting the radius value into the formula, the area of the circle is π(4)² = 16π cm². Therefore, the correct answer is 16π cm². Choice A (18π cm²), B (10π cm²), and D (8π cm²) are incorrect because they do not represent the area of the largest circle that fits inside the given rectangle.

5. What are the tiny contractile units within muscle cells called?

• A. Myocytes
• B. Myofibrils
• C. Sarcomeres
• D. Tendons

Correct answer: C

Rationale: Sarcomeres are the smallest contractile units within muscle cells. They consist of overlapping filaments of actin and myosin proteins, which interact to produce muscle contractions. Myocytes are the entire muscle cells, myofibrils are bundles of protein filaments found within muscle cells, and tendons are tough connective tissues that connect muscles to bones. Therefore, sarcomeres specifically represent the contractile units responsible for muscle contraction, making them the correct answer in this context.

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