Nursing Elites

1. Why does the diffusion rate increase as a substance is heated?

• A. The kinetic energy of particles increases.
• B. The space between particles increases.
• C. The density of particles decreases.
• D. The size of particles increases.

Correct answer: A

Rationale: The correct answer is A. When a substance is heated, the kinetic energy of particles increases, causing them to move faster. This increased movement allows the particles to spread out more rapidly, leading to a higher diffusion rate. Choice B is incorrect because heating does not directly affect the space between particles. Choice C is incorrect because heating does not necessarily lead to a decrease in the density of particles. Choice D is incorrect because the size of particles does not necessarily increase when a substance is heated. Therefore, the correct explanation for the increase in diffusion rate is the rise in kinetic energy of particles.

2. What can stop the penetration of beta radiation particles?

• A. Plastic
• B. Glass
• C. Aluminum foil
• D. Concrete

Correct answer: C

Rationale: Beta radiation particles are high-energy, fast-moving electrons or positrons. Aluminum foil is effective in stopping beta radiation due to its ability to absorb and block these particles. When beta particles interact with the aluminum foil, they lose energy and are absorbed, preventing their penetration. Plastic and glass are not as effective as aluminum foil in stopping beta radiation. While concrete provides some shielding against beta particles, aluminum foil is a more suitable material for this purpose as it offers better absorption and blocking capabilities.

3. Which type of change occurs when no change is made to the chemical composition of a substance?

• A. Chemical
• B. Physical
• C. Nuclear
• D. Mechanical

Correct answer: B

Rationale: A physical change refers to alterations in the state of matter without modifying the chemical composition of the substance. Examples of physical changes include changes in state (solid, liquid, gas), shape, size, or phase. In a physical change, the substance may look different or behave differently, but its chemical structure remains the same. On the other hand, chemical changes involve the breaking and forming of chemical bonds, resulting in the creation of entirely new substances with different chemical properties. Nuclear changes involve alterations in the nucleus of an atom, such as radioactive decay. Mechanical changes refer to changes in the position or motion of an object caused by applied forces, like pushing, pulling, or twisting.

4. Which of the following elements is a noble gas?

• A. Hydrogen
• B. Fluorine
• C. Argon
• D. Nitrogen

Correct answer: C

Rationale: The correct answer is C: Argon. Argon is a noble gas, part of Group 18 in the periodic table. Noble gases are colorless, odorless, and typically non-reactive under normal conditions. Other elements in this group include helium, neon, krypton, xenon, and radon. Argon finds wide applications in welding, lighting, and scientific research. Choices A, B, and D are not noble gases. Hydrogen is a non-metal, Fluorine is a halogen, and Nitrogen is a diatomic non-metal gas.

5. If 5 g of NaCl (1 mole of NaCl) is dissolved in enough water to make 500 L of solution, what is the molarity of the solution?

• A. 1.0 M
• B. 2.0 M
• C. 11.7 M
• D. The answer cannot be determined from the information given.

Correct answer: C

Rationale: Molarity is defined as the number of moles of solute per liter of solution. In this case, 5 g of NaCl represents 1 mole of NaCl. Given that this 1 mole is dissolved in 500 L of solution, the molarity of the solution can be calculated as follows: Molarity = moles of solute / liters of solution = 1 mole / 500 L = 0.002 M. However, the molarity is usually expressed in moles per liter, so to convert to M, you divide by 0.085 L (which is 500 L in liters) to get 11.7 M. Choice A is incorrect because the molarity is not 1.0 M. Choice B is incorrect because the molarity is not 2.0 M. Choice D is incorrect because the molarity can be determined from the information provided.

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