Nursing Elites

1. When sugar is heated, it breaks down into carbon and water vapor. This is an example of a:

• A. Combination reaction
• B. Decomposition reaction
• C. Double displacement reaction
• D. Single displacement reaction

Correct answer: B

Rationale: The correct answer is B: Decomposition reaction. When sugar is heated, it undergoes a decomposition reaction where it breaks down into simpler substances, carbon, and water vapor. In a decomposition reaction, a single compound breaks down into two or more simpler substances. This process is the opposite of a combination reaction where two or more substances combine to form a new compound. Choice A, Combination reaction, is incorrect because a combination reaction involves the combination of two or more substances to form a new compound, which is the opposite of what happens when sugar breaks down. Choices C and D, Double displacement reaction and Single displacement reaction, are incorrect as they involve different mechanisms where the atoms or ions of the reactants are exchanged, which is not the case in the breakdown of sugar into carbon and water vapor.

2. What type of bond holds water molecules together?

• A. Covalent bond
• B. Hydrogen bond
• C. Ionic bond
• D. Peptide bond

Correct answer: B

Rationale: The correct answer is B: Hydrogen bond. Hydrogen bonds are responsible for holding water molecules together. In a water molecule, the oxygen atom is slightly negative, and the hydrogen atoms are slightly positive, creating a partial positive and negative charge. This polarity allows hydrogen bonds to form between adjacent water molecules. Covalent bonds involve the sharing of electrons, ionic bonds involve transfer of electrons between ions, and peptide bonds are specific to linking amino acids in proteins, which are not relevant to water molecule interactions.

3. Which of the following body systems controls fluid loss, protects deep tissues, and synthesizes vitamin D?

• A. The skeletal system
• B. The muscular system
• C. The lymphatic system
• D. The integumentary system

Correct answer: D

Rationale: The integumentary system is responsible for controlling fluid loss through sweat, protecting deep tissues as the body's first line of defense, and synthesizing vitamin D when exposed to sunlight. The skin, hair, nails, and associated glands make up the integumentary system, which plays a crucial role in maintaining homeostasis and overall health. The skeletal system (Choice A) provides structural support and protection for internal organs but does not directly control fluid loss, protect deep tissues, or synthesize vitamin D. The muscular system (Choice B) is responsible for movement and stability but is not involved in the functions described. The lymphatic system (Choice C) is primarily responsible for immunity and fluid balance, not the specific functions mentioned in the question.

4. Which of the following is the primary physical barrier the body uses to prevent infection?

• A. mucus membranes
• B. stomach acid
• C. skin
• D. urine

Correct answer: C

Rationale: The correct answer is 'C: skin.' The skin is the primary physical barrier the body uses to prevent infection. It acts as a protective shield that prevents harmful microorganisms from entering the body. The outer layer of the skin, known as the epidermis, acts as a tough physical barrier that blocks the entry of pathogens. Additionally, the skin has special immune cells that can help fight off invaders that manage to breach the physical barrier. Choices A, B, and D are incorrect. While mucous membranes, stomach acid, and urine play important roles in the body's defense against pathogens, the primary physical barrier is the skin, which covers the entire body and provides a robust protective barrier.

5. What is the relationship between work and energy?

• A. Work is the rate of energy transfer
• B. Work and energy are the same concepts
• C. Work is the result of energy
• D. Work changes an object's energy from one form to another

Correct answer: A

Rationale: Work is defined as the transfer of energy from one system to another. It is the rate at which energy is transferred or converted. Therefore, work is the rate of energy transfer, making option A the correct choice. Work involves the transfer or conversion of energy, but it is not the same as energy itself, nor is it the result of energy. Additionally, work does not change an object's energy from one form to another; instead, it involves the transfer of energy.

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