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. Which of the following blood proteins can destroy pathogens?

• A. Complement system
• B. Fibrinogen
• C. Major histocompatibility complex
• D. Platelets

Correct answer: A

Rationale: The correct answer is A: Complement system. The complement system is a vital component of the immune system responsible for destroying pathogens through various mechanisms like promoting inflammation, enhancing phagocytosis, and directly lysing pathogens. Fibrinogen is crucial for blood clotting, the major histocompatibility complex is involved in immune responses, and platelets aid in blood clotting and wound healing. However, none of these directly destroy pathogens as the complement system does.

3. Which of these body parts does not contain melanin?

• A. Hair
• B. Nails
• C. Skin
• D. Iris

Correct answer: D

Rationale: The iris is the colored part of the eye that determines the eye's color. Melanin is not present in the iris, unlike hair, nails, and skin. Melanin gives color to hair, nails, and skin, but not to the iris. Therefore, the correct answer is the iris (Choice D). Choices A, B, and C contain melanin and are incorrect.

4. What is the muscular sac in the female body that nourishes and protects a developing fetus?

• A. Ovary
• B. Fallopian tube
• C. Uterus
• D. Vagina

Correct answer: C

Rationale: The correct answer is the uterus. The uterus is a muscular organ in the female body where a fertilized egg implants and grows into a fetus during pregnancy. It provides nourishment and protection to the developing fetus. The ovaries produce eggs, the fallopian tubes transport eggs from the ovaries to the uterus, and the vagina is the muscular tube that connects the uterus to the outside of the body for childbirth. Therefore, the roles of the ovary, fallopian tube, and vagina are not related to nourishing and protecting a developing fetus, making them incorrect choices.

5. What lab equipment would most likely be used to precisely measure the volume of a liquid solution?

• A. Flask
• B. Triple beam balance
• C. Graduated cylinder
• D. Test tube

Correct answer: C

Rationale: A graduated cylinder is the most suitable lab equipment for precisely measuring the volume of a liquid solution. Graduated cylinders are designed with calibrated markings that allow for accurate volume measurements of liquids. The other choices are not appropriate for measuring liquid volume: Flasks are used for mixing or storing liquids, triple beam balances are used for measuring mass, and test tubes are typically used for holding small amounts of substances during experiments.

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