Nursing Elites

1. What is the name of the phase change from liquid to gas?

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

Correct answer: C

Rationale: The correct answer is 'Evaporation.' This phase change occurs when a liquid turns into a gas. During evaporation, molecules gain enough energy to break free from the liquid phase and enter the gas phase, without the need for the liquid to reach its boiling point. Choice A, 'Condensation,' is the opposite phase change where gas turns into a liquid. Choice B, 'Sublimation,' is the phase change from solid directly to gas, skipping the liquid phase. Choice D, 'Melting,' is the phase change from solid to liquid.

2. Which best defines the molarity of an aqueous sugar solution?

• A. Grams of sugar per milliliter of solution
• B. Moles of sugar per milliliter of solution
• C. Grams of sugar per liter of solution
• D. Moles of sugar per liter of solution

Correct answer: D

Rationale: The molarity of a solution is defined as the number of moles of solute per liter of solvent. In the case of an aqueous sugar solution, the molarity would be expressed as moles of sugar per liter of solution. This is because molarity is a measurement of the concentration of a solute in a solution based on the number of moles present in a given volume of the solution. Therefore, the correct answer is D. Choices A, B, and C are incorrect because the molarity is specifically defined in terms of moles of solute per liter of solution, not in grams per milliliter or grams per liter. Molarity is a unit of concentration that relates the amount of solute to the volume of the solution, not the mass of the solute.

3. To the nearest whole number, what is the mass of one mole of hydrogen chloride?

• A. 36 g/mol
• B. 38 g/mol
• C. 71 g/mol
• D. 74 g/mol

Correct answer: C

Rationale: The molar mass of hydrogen chloride (HCl) is calculated by adding the atomic masses of hydrogen (H) and chlorine (Cl) together. The atomic mass of hydrogen is approximately 1 g/mol, and the atomic mass of chlorine is approximately 35.5 g/mol. Therefore, the molar mass of hydrogen chloride (HCl) is approximately 1 + 35.5 = 36.5 g/mol. When rounded to the nearest whole number, it is 36 g/mol. Therefore, the correct answer is 36 g/mol. Choices A, B, and D are incorrect as they do not reflect the accurate molar mass of hydrogen chloride.

4. What is the name for the horizontal rows of the periodic table?

• A. groups
• B. periods
• C. families
• D. sets

Correct answer: B

Rationale: In the periodic table, 'periods' are the horizontal rows. Each period corresponds to the energy level occupied by the elements in that row. The other terms mentioned, such as groups, families, and sets, are not used to describe the horizontal rows but rather refer to different aspects of the periodic table organization. 'Groups' are the vertical columns, 'families' are groups of elements with similar properties, and 'sets' is a more generic term not specifically used in the context of the periodic table.

5. What is atomic mass?

• A. Number of protons in an atom
• B. Sum of protons and neutrons
• C. Number of neutrons in an atom
• D. Average weight of an element

Correct answer: B

Rationale: Atomic mass, also known as atomic weight, is the sum of the number of protons and neutrons in an atom. It represents the average mass of an atom of an element, taking into account the different isotopes and their relative abundance. Neutrons contribute to the atomic mass alongside protons, while the number of neutrons alone is not the definition of atomic mass. Choice A is incorrect because it refers only to the number of protons, not the complete atomic mass. Choice C is incorrect as it focuses solely on the number of neutrons, excluding the contribution of protons. Choice D is incorrect as it mentions the 'average weight of an element,' which is related to atomic mass but does not encapsulate the specific definition of atomic mass as the sum of protons and neutrons.

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