Nursing Elites

1. Which substance has a pH value greater than 7?

• A. Water
• B. Vinegar
• C. Lemon juice
• D. Baking soda

Correct answer: D

Rationale: The correct answer is D, Baking soda. Baking soda has a pH greater than 7, making it basic. pH values above 7 indicate alkalinity, and baking soda, being a base, has a pH higher than 7. Water, vinegar, and lemon juice have pH values below 7, indicating acidity. Water is neutral with a pH of 7, while vinegar and lemon juice are acidic with pH values lower than 7.

2. When balanced, the reaction Fe + O₂ → FeO will be?

• A. 2Fe + 2O₂ → 3FeO
• B. 4Fe + 6O₂ → 6FeO
• C. 2Fe + 3O₂ → 2FeO
• D. 4Fe + 3O₂ → 2FeO

Correct answer: C

Rationale: To balance the chemical equation Fe + O₂ → FeO, the coefficients needed are 2 for Fe and 1 for O. Therefore, the balanced equation becomes 2Fe + O₂ → 2FeO, which translates into 2Fe + 3O₂ → 2FeO. This corresponds to option C. Choice A has the incorrect number of oxygen molecules. Choice B has an incorrect number of Fe atoms on the product side. Choice D also has an incorrect number of Fe atoms on the product side.

3. Which element has the highest atomic number?

• A. Uranium
• B. Hydrogen
• C. Radon
• D. Bismuth

Correct answer: A

Rationale: The correct answer is Uranium. The atomic number represents the number of protons in an atom's nucleus. Among the options provided, Uranium has the highest atomic number, which is 92. Hydrogen has an atomic number of 1, Radon has an atomic number of 86, and Bismuth has an atomic number of 83. Therefore, Uranium is the element with the highest atomic number in the given choices.

4. What is the correct formula for sodium nitrate?

• A. NaNO
• B. Na NO
• C. NaNO₃
• D. Na NO₂

Correct answer: C

Rationale: The correct formula for sodium nitrate is NaNO₃. In this formula, 'Na' represents sodium, 'N' represents nitrogen, and 'O₃' represents three oxygen atoms. Sodium nitrate consists of one sodium ion (Na⁺) and one nitrate ion (NO₃⁻), which means the correct formula is NaNO₃. Choice A (NaNO) is incorrect as it lacks the subscript indicating the presence of three oxygen atoms. Choice B (Na NO) is incorrect as it includes a space between 'Na' and 'NO', which is not part of the standard chemical formula notation. Choice D (Na NO₂) is incorrect as it indicates a different compound with a nitrite ion (NO₂⁻) instead of nitrate ion.

5. Which element is a metalloid?

• A. Silicon
• B. Lead
• C. Helium
• D. Aluminum

Correct answer: A

Rationale: The correct answer is 'Silicon.' Silicon is a metalloid, which means it has properties of both metals and nonmetals. It is commonly used in electronic devices due to its semiconductor properties. Lead (Choice B) is a metal, Helium (Choice C) is a noble gas, and Aluminum (Choice D) is a metal.

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