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. What is the oxidation state of the potassium ion in the compound KCl?

• A. +1
• B. -1
• C. +2
• D. -2

Correct answer: A

Rationale: In the compound KCl (potassium chloride), potassium is in Group 1 of the periodic table, which means it has a valence electron of 1. Chlorine is in Group 17 and gains one electron to achieve a stable electron configuration by forming an ionic bond with potassium. As a result, the potassium ion in KCl has a +1 oxidation state. Therefore, the correct answer is +1. Choices B, C, and D are incorrect as they do not reflect the oxidation state of the potassium ion in KCl.

3. What is an alloy in which another metal is dissolved in mercury (Hg) called?

• A. Electrum
• B. Amalgam
• C. Solder
• D. Bronze

Correct answer: B

Rationale: An amalgam is a type of alloy where another metal is dissolved in mercury (Hg). This process forms a unique mixture that has various applications in dentistry, chemistry, and other fields. Electrum is a natural alloy of gold and silver, solder is a metal alloy used to join other metals together, and bronze is a copper-tin alloy. Therefore, the correct answer is B - Amalgam.

4. If gas A has four times the molar mass of gas B, you would expect it to diffuse through a plug ___________.

• A. at half the rate of gas B
• B. at twice the rate of gas B
• C. at a quarter the rate of gas B
• D. at four times the rate of gas B

Correct answer: A

Rationale: When comparing the diffusion rates of two gases, according to Graham's law of diffusion, the rate of diffusion is inversely proportional to the square root of the molar mass. If gas A has four times the molar mass of gas B, the square root of the molar masses ratio (4:1) is 2. This means that gas A would diffuse through a plug at half the rate of gas B. Therefore, the correct answer is A, at half the rate of gas B. Choices B, C, and D are incorrect because they do not reflect the correct relationship between the molar masses and the rates of diffusion according to Graham's law.

5. If electrons are shared equally in a covalent bond, the bond is classified as what?

• A. Polar
• B. Non-polar
• C. Ionic
• D. Hydrogen

Correct answer: B

Rationale: The correct answer is B: Non-polar. In a non-polar covalent bond, electrons are shared equally between the atoms involved, leading to a balanced distribution of charge and no significant difference in electronegativity between the atoms. This equal sharing results in a non-polar bond. Choices A, C, and D are incorrect because a polar bond involves an unequal sharing of electrons, an ionic bond is formed by the transfer of electrons, and a hydrogen bond is a specific type of non-covalent bond.

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