Nursing Elites

1. Which type of chemical reaction involves two ionic compounds where the reactants yield 'switched partners'?

• A. Single replacement
• B. Double replacement
• C. Synthesis
• D. Decomposition

Correct answer: B

Rationale: The correct answer is 'Double replacement.' In a double replacement reaction, two ionic compounds react by exchanging ions, resulting in the formation of two new compounds where the positive and negative ions have 'switched partners.' This type of reaction is characterized by the exchange of ions between the reactants. Choice A, 'Single replacement,' involves an element replacing another in a compound, not the exchange of partners like in the given scenario. Choice C, 'Synthesis,' is the combination of two or more substances to form a more complex product, not involving the exchange of partners. Choice D, 'Decomposition,' is the breakdown of a compound into simpler substances, which is different from the scenario described in the question.

2. What is the energy required to remove the outermost electron from an atom called?

• A. covalent bonding
• B. electronegativity
• C. atomic radius
• D. ionization energy

Correct answer: D

Rationale: Ionization energy is the energy needed to remove the outermost electron from an atom, resulting in the formation of a positively charged ion. The higher the ionization energy, the more difficult it is to extract an electron. Electronegativity, however, measures an atom's ability to attract shared electrons in a chemical bond. Atomic radius refers to the distance from the nucleus to the outermost electron. Covalent bonding involves sharing electron pairs between atoms to create a stable bond. Therefore, the correct answer is ionization energy as it specifically relates to the energy needed to remove an electron from an atom.

3. Which statement is true of a saturated solution?

• A. It has more solute than can dissolve in the solvent.
• B. It has less solute that can dissolve in the solvent.
• C. It has the maximum concentration of the solute dissolved in the solvent.
• D. It contains a precipitate that lowers the concentration of the solute in the solvent.

Correct answer: C

Rationale: A saturated solution contains the maximum concentration of solute that can be dissolved in a specific amount of solvent at a particular temperature. Once a solution is saturated, adding more solute will not increase its concentration since the excess solute will not dissolve and will instead form a precipitate, indicating that the solution is at its maximum capacity. Choices A, B, and D are incorrect because a saturated solution has reached its limit in dissolving solute, so it cannot contain more solute than it can dissolve (choice A), less solute than it can dissolve (choice B), or a precipitate that lowers the concentration of the solute in the solvent (choice D).

4. What is the pH of a neutral solution?

• A. 7
• B. 0
• C. 14
• D. 4

Correct answer: A

Rationale: The correct answer is A: 7. A neutral solution has a pH of 7. In the pH scale, values below 7 are acidic, 7 is neutral, and values above 7 are basic. Therefore, a solution with a pH of 7 is considered neutral as it is neither acidic nor basic. Choices B, C, and D are incorrect because a pH of 0 indicates a strong acid, a pH of 14 indicates a strong base, and a pH of 4 indicates an acidic solution. None of these values represent a neutral solution.

5. What does the mass number minus the atomic number equal?

• A. Number of electrons
• B. Number of neutrons
• C. Number of protons
• D. Number of isotopes

Correct answer: B

Rationale: The mass number of an atom represents the total number of protons and neutrons in its nucleus. The atomic number indicates the number of protons in the nucleus. The difference between the mass number and the atomic number provides the number of neutrons present in the nucleus of an atom. Therefore, mass number minus atomic number equals the number of neutrons. Choice A is incorrect because the number of electrons is not determined by the mass number and atomic number. Choice C is incorrect as it represents the number of protons, not the difference between the mass number and atomic number. Choice D is incorrect as isotopes refer to atoms of the same element with different numbers of neutrons, not the difference between mass number and atomic number.

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