Nursing Elites

1. What is matter that has a definite shape and volume?

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

Correct answer: B

Rationale: Matter that has a definite shape and volume is referred to as a solid. Solids maintain their shape and volume under normal conditions, unlike liquids that have a definite volume but take the shape of their container, gases that have neither a definite shape nor volume, and plasma which is a state of matter with no definite shape or volume and consists of charged particles.

2. What does the mass of one mole of a substance represent?

• A. Atomic mass
• B. Mass number
• C. Molecular weight
• D. Molar mass

Correct answer: D

Rationale: The mass of one mole of a substance is represented by its molar mass. Molar mass is the mass of one mole of a substance and is expressed in grams per mole. It is calculated by summing the atomic masses of all atoms in a molecule. Therefore, the correct answer is D - 'Molar mass'. Choice A, 'Atomic mass', refers to the average mass of an atom of an element. Choice B, 'Mass number', is the total number of protons and neutrons in an atom's nucleus. Choice C, 'Molecular weight', is the average mass of a molecule relative to 1/12 of the mass of an atom of carbon-12.

3. What is the name of the process by which a gas turns into a liquid?

• A. Sublimation
• B. Condensation
• C. Evaporation
• D. Deposition

Correct answer: B

Rationale: The correct answer is B: Condensation. Condensation is the process where gas transforms into a liquid. When gas cools down, it loses energy and its particles come closer, leading to the formation of liquid droplets. Sublimation is the direct transition from solid to gas without passing through the liquid state. Evaporation is the process of liquid turning into a gas, and deposition is the transition of gas directly into a solid. Therefore, choices A, C, and D are incorrect as they describe different phase transitions.

4. A radioactive isotope has a half-life of 20 years. How many grams of a 6-gram sample will remain after 40 years?

• A. 8
• B. 6
• C. 3
• D. 1.5

Correct answer: C

Rationale: The half-life of a radioactive isotope is the time it takes for half of the original sample to decay. After each half-life period, half of the initial sample remains. In this case, after the first 20 years, half of the 6-gram sample (3 grams) will remain. After another 20 years (total of 40 years), half of the remaining 3 grams will remain, which is 1.5 grams. Therefore, 3 grams will be left after 40 years. Choice A is incorrect as it doesn't consider the concept of half-life and incorrectly suggests an increase in the sample. Choice B is incorrect as it assumes no decay over time. Choice D is incorrect as it miscalculates the remaining amount after two half-life periods.

5. Which two elements are most alike in reactivity?

• A. He and H
• B. K and Ar
• C. Cl and P
• D. Ba and Mg

Correct answer: C

Rationale: Chlorine (Cl) and Phosphorus (P) are most alike in reactivity among the given pairs. Both elements are nonmetals and belong to Group 7 (halogens) and Group 15 (nitrogen group), respectively. They have similar electronic configurations and can form compounds by gaining or sharing electrons. Chlorine is highly reactive and can easily form ionic compounds, while phosphorus also shows a range of reactivity in its compounds. Choice A (He and H) is incorrect because helium (He) is a noble gas and hydrogen (H) is a nonmetal, so they are not similar in reactivity. Choice B (K and Ar) is incorrect as potassium (K) is a metal and argon (Ar) is a noble gas, having different reactivities. Choice D (Ba and Mg) is incorrect because barium (Ba) and magnesium (Mg) are both metals, but their reactivities differ due to their positions in the periodic table.

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