Nursing Elites

1. How do hydrogen bonds in water affect its characteristics?

• A. Hydrogen bonds are not polar enough to attract non-polar molecules.
• B. Hydrogen bonds cause water to be less dense when it is a solid than when it is a liquid.
• C. Hydrogen bonds cause water to have high surface tension, allowing some organisms to move across it.
• D. Hydrogen bonds cause water to be a good solvent.

Correct answer: C

Rationale: Hydrogen bonds in water contribute to its high surface tension, enabling some organisms to move across the water's surface. This property is essential for certain insects and small animals that rely on surface tension to move or stay afloat on water. Choice A is incorrect because hydrogen bonds are polar and can attract polar and other charged molecules. Choice B is incorrect as hydrogen bonds make ice less dense than liquid water, which is a unique property. Choice D is incorrect as the ability of water to act as a good solvent is primarily due to its polarity, not just hydrogen bonding.

2. What is the main function of the skeletal system?

• A. To regulate blood pressure
• B. To protect internal organs
• C. To produce hormones
• D. To fight infection

Correct answer: B

Rationale: The main function of the skeletal system is to provide structural support for the body, protect internal organs, facilitate movement, and produce blood cells in the bone marrow. Choice A, 'To regulate blood pressure,' is incorrect as blood pressure regulation is primarily controlled by the circulatory and endocrine systems. Choice C, 'To produce hormones,' is incorrect as hormone production is mainly carried out by the endocrine system. Choice D, 'To fight infection,' is incorrect as the immune system is responsible for fighting infections, not the skeletal system.

3. Salts are formed by the reaction between:

• A. Two acids
• B. An acid and a base
• C. Two bases
• D. A metal and a nonmetal only

Correct answer: B

Rationale: Salts are formed by the reaction between an acid and a base. This reaction is known as a neutralization reaction. In this reaction, the acid donates a proton (H+) to the base, resulting in the formation of water and a salt as the products. Choice A is incorrect because salts are not formed by the reaction of two acids. Choice C is incorrect as salts are not produced by the reaction of two bases. Choice D is incorrect because while salts can be formed from the reaction between a metal and a nonmetal, it is not the only way salts are produced.

4. What is the formula for the area of a circle?

• A. A = πr²
• B. A = 2πr
• C. A = πd
• D. A = 2πd

Correct answer: A

Rationale: The correct formula for the area of a circle is A = πr², where π is a mathematical constant approximately equal to 3.14159 and r is the radius of the circle. Choice B, A = 2πr, represents the circumference of a circle, not the area. Choice C, A = πd, incorrectly uses the diameter (d) instead of the radius in the formula for area. Choice D, A = 2πd, is also related to the circumference of the circle, not the area. Therefore, option A is the only correct formula for calculating the area of a circle.

5. Which of the following equations correctly models the relationship between x and y when y is three times x?

• A. y = 3x
• B. x = 3y
• C. y = x + 3
• D. y = x / 3

Correct answer: A

Rationale: The correct equation that models the relationship between x and y when y is three times x is y = 3x. This equation represents that y is equal to three times x. Choice B (x = 3y) incorrectly reverses the relationship, stating that x is equal to three times y. Choice C (y = x + 3) and Choice D (y = x / 3) do not correctly represent a relationship where y is three times x, making them incorrect choices.

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