Nursing Elites

1. In which state of matter are particles packed tightly together in a fixed position?

• A. Liquid
• B. Solid
• C. Gas
• D. Plasma

Correct answer: B

Rationale: In a 'solid' state, particles are tightly packed in fixed positions, maintaining a definite shape and volume. This arrangement allows solids to maintain a rigid structure. Liquids have particles that are close together but can move past each other, giving them the ability to flow and take the shape of their container. Gases have particles that are far apart and move freely, leading to their ability to expand to fill any container. Plasma is an ionized gas where particles have high energy levels and are not packed tightly together, making it an uncommon state of matter on Earth.

2. Radioactive isotopes are frequently used in medicine. What kind of half-life would a medical isotope probably have?

• A. Seconds-long
• B. Days-long
• C. Years-long
• D. Many years long

Correct answer: B

Rationale: Medical isotopes used in diagnosis and treatment need to have a relatively short half-life to minimize radiation exposure to patients. If the half-life were too long (such as many years) or even years-long, the radiation would persist for too long and could be harmful to the patient. Seconds-long half-lives would not provide enough time for the isotope to be effective. Days-long half-lives strike a balance between providing enough time for the isotope to be used effectively and minimizing radiation exposure.

3. What can stop the penetration of alpha particles?

• A. Aluminum foil
• B. Glass
• C. Piece of paper
• D. Plastic

Correct answer: C

Rationale: Alpha particles can be stopped by a piece of paper due to their low penetration power. The paper acts as a shield, effectively blocking the alpha particles from passing through. In contrast, materials like aluminum foil, glass, and plastic are not as effective as a simple piece of paper in stopping alpha particles. Aluminum foil is more effective against beta particles, gamma rays, and x-rays due to its higher density. Glass and plastic also provide some protection against beta particles and gamma rays, but they are less effective than a piece of paper against alpha particles.

4. If electrons are not shared equally in a covalent bond, the bond is what?

• A. Polar
• B. Non-polar
• C. Ionic
• D. Hydrogen

Correct answer: A

Rationale: A polar covalent bond occurs when electrons are shared unequally between atoms. In this type of bond, one atom has a stronger pull on the shared electrons, leading to a partial positive and partial negative charge distribution within the molecule. Choice B, non-polar, is incorrect because in non-polar covalent bonds, electrons are shared equally between atoms. Choice C, ionic, is incorrect as ionic bonds involve a transfer of electrons rather than sharing. Choice D, hydrogen, is incorrect as it does not describe the nature of a covalent bond.

5. Here are the solubilities of four substances at 0°C, in grams of solute per 100 mL of water. If the temperature increases to 20°C, what would you expect to happen to the solubility figures?

• A. Citric acid and potassium phosphate will decrease; nitrogen and oxygen will increase.
• B. Citric acid and potassium phosphate will increase; nitrogen and oxygen will decrease.
• C. All four figures will increase.
• D. All four figures will decrease.

Correct answer: C

Rationale: Solubility generally tends to increase with temperature for most solid solutes in liquid solvents due to higher kinetic energy leading to better solute-solvent interactions. As the temperature increases from 0°C to 20°C, all four solubility figures are expected to increase. Choice A is incorrect because solubility tends to increase with temperature. Choice B is incorrect as well for the same reason. Choice D is incorrect because the solubility of solid solutes typically increases with temperature.

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