Nursing Elites

1. Which of the following properties is NOT characteristic of a covalent bond?

• A. Sharing of electrons between atoms
• B. High melting and boiling points
• C. Low electrical conductivity in solid state
• D. Directional bonding

Correct answer: B

Rationale: Covalent bonds are formed by the sharing of electrons between atoms, leading to the formation of molecules with directional bonding. This means that the atoms are held together in a specific orientation. Covalent compounds generally exhibit low melting and boiling points compared to ionic compounds due to the weaker intermolecular forces present in covalent compounds. Furthermore, covalent compounds do not conduct electricity in the solid state because the electrons are localized between the atoms and are not free to move and carry charge. Hence, high melting and boiling points are not characteristic of covalent bonds. The correct answer is 'B' because high melting and boiling points are typically associated with ionic compounds due to their strong electrostatic interactions, while covalent compounds have lower melting and boiling points. Choices A, C, and D are all characteristics of covalent bonds, making them incorrect answers for this question.

2. What causes lymphedema, a chronic condition, to occur?

• A. Inflammation of lymph nodes
• B. Blockage of lymph vessels
• C. Malfunction of the spleen
• D. Decrease in bone marrow production

Correct answer: B

Rationale: Lymphedema is a chronic condition that occurs when lymph vessels become blocked, leading to swelling and fluid retention in the affected area. Inflammation of lymph nodes, spleen malfunction, or decreased bone marrow production are not directly associated with the development of lymphedema. Lymph vessels play a crucial role in carrying lymphatic fluid, and when they are blocked, it disrupts the normal flow of fluid, resulting in lymphedema. Therefore, the correct answer is that lymphedema occurs when lymph vessels become blocked.

3. What happens to the acceleration of an object when the force acting on it is increased, assuming the mass remains constant?

• A. Acceleration increases
• B. Acceleration decreases
• C. Acceleration remains constant
• D. Acceleration becomes zero

Correct answer: A

Rationale: According to Newton's second law of motion, acceleration is directly proportional to the force acting on an object when the mass is constant. Therefore, if the force acting on an object is increased while the mass remains constant, the acceleration of the object will also increase. This relationship is described by the formula F = ma, where F is the force applied, m is the mass of the object, and a is the acceleration. When force increases, acceleration increases, and vice versa, as long as the mass stays the same. Choice B (Acceleration decreases) is incorrect because acceleration and force have a direct relationship. Choice C (Acceleration remains constant) is incorrect because acceleration changes in response to changes in force. Choice D (Acceleration becomes zero) is incorrect because increasing force does not make acceleration zero; it actually increases it.

4. What type of bond is present in salt?

• A. Ionic
• B. Nonpolar covalent
• C. Polar covalent
• D. Peptide

Correct answer: A

Rationale: The correct answer is 'Ionic.' Ionic bonds are formed in salts through the transfer of electrons between atoms, leading to the attraction between positively and negatively charged ions. This results in a stable ionic compound, such as common table salt (sodium chloride). Nonpolar covalent, polar covalent, and peptide bonds are not typically found in salts. Nonpolar covalent bonds involve the equal sharing of electrons, polar covalent bonds involve unequal sharing of electrons, and peptide bonds are specific to proteins, not salts.

5. Osteoporosis is a condition that leads to weakened bones and an increased risk of fractures. Which hormone plays a key role in bone health and is often affected in osteoporosis?

• A. Estrogen
• B. Testosterone
• C. Thyroid hormone
• D. Insulin

Correct answer: A

Rationale: Estrogen plays a crucial role in maintaining bone health by inhibiting bone resorption and promoting bone formation. In postmenopausal women, estrogen levels decrease, leading to an increased risk of osteoporosis due to accelerated bone loss. This hormonal imbalance contributes to weakened bones and an increased risk of fractures in individuals with osteoporosis. Testosterone and thyroid hormone do play roles in bone health, but estrogen has a more significant impact. Testosterone is more commonly associated with muscle mass and strength, while thyroid hormone regulates metabolism. Insulin is not directly involved in bone health and is not typically affected in osteoporosis.

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