Nursing Elites

1. Which of the following substances is a common base found in household products?

• A. Sodium chloride (NaCl)
• B. Ammonia (NH₃)
• C. Vinegar
• D. Lemon juice

Correct answer: B

Rationale: The correct answer is B, Ammonia (NH₃). Ammonia is commonly found in household products and is used in cleaning agents due to its alkaline properties. Sodium chloride (NaCl) is a common salt and not a base. Vinegar is acetic acid, which is acidic in nature. Lemon juice contains citric acid, making it acidic as well. Therefore, ammonia is the only base among the choices provided.

2. Which indicator is commonly used to distinguish between acidic and basic solutions?

• A. Methyl orange
• B. Phenolphthalein
• C. Universal indicator
• D. All of the above are common indicators.

Correct answer: B

Rationale: Phenolphthalein is commonly used to differentiate between acidic and basic solutions. It changes color, turning pink in basic solutions and remaining colorless in acidic solutions due to a specific pH range. While methyl orange and universal indicator are also indicators used for pH testing, phenolphthalein is especially known for its distinctive color change in response to acidic and basic solutions, making it the correct choice. Methyl orange is typically used in titrations for a sharp color change at a specific pH, and the universal indicator is a mixture of indicators displaying a range of colors depending on the pH value, not specifically tailored to acidic and basic distinctions.

3. Which of the following salt solutions is most likely to conduct electricity well?

• A. A saturated solution
• B. A concentrated solution of a strong electrolyte
• C. A dilute solution of a weak acid
• D. A mixture of a neutral compound and water

Correct answer: B

Rationale: A concentrated solution of a strong electrolyte is most likely to conduct electricity well. Strong electrolytes completely dissociate into ions in solution, allowing for the flow of electric current. This high concentration of ions in the solution enhances its conductivity, making it a better conductor compared to other options. A saturated solution, although containing dissolved ions, may not have a high enough concentration to conduct electricity effectively. A dilute solution of a weak acid is a poor conductor as weak acids only partially dissociate into ions. A mixture of a neutral compound and water does not contain free ions necessary for conducting electricity.

4. What is the primary function of DNA polymerase?

• A. Packaging DNA
• B. Replicating DNA
• C. Transcribing DNA
• D. Translating mRNA

Correct answer: B

Rationale: The correct answer is B: Replicating DNA. DNA polymerase is an enzyme responsible for synthesizing new DNA strands during DNA replication. It adds nucleotides to the growing DNA strand based on the template provided by the existing DNA strand. This process ensures that genetic information is accurately copied and passed on to daughter cells during cell division. Option A, Packaging DNA, refers to the coiling and organization of DNA into chromatin, a process involving histones and other proteins. Option C, Transcribing DNA, involves the synthesis of RNA from a DNA template, a process carried out by RNA polymerase. Option D, Translating mRNA, refers to the process of protein synthesis where the information encoded in mRNA is used to assemble amino acids into a polypeptide chain.

5. What does the term 'electron configuration' refer to in relation to an atom?

• A. The arrangement of electrons in an atom's orbitals.
• B. The number of protons in an atom's nucleus.
• C. The number of neutrons in an atom's nucleus.
• D. The number of electrons in an atom's valence shell.

Correct answer: A

Rationale: The electron configuration of an atom refers to the arrangement of electrons in the atom's orbitals. This arrangement determines the atom's chemical properties and behavior. The number of protons in an atom's nucleus (option B) is known as the atomic number, which defines the element. The number of neutrons in an atom's nucleus (option C) contributes to the atom's mass number. The number of electrons in an atom's valence shell (option D) is important for understanding the atom's reactivity and bonding behavior, but the electron configuration specifically refers to how electrons are distributed among the different orbitals in an atom.

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