Nursing Elites

1. You contain two odorous gases in vials with porous plugs. Gas A has twice the mass of Gas B. Which observation is most likely?

• A. You will smell Gas A before you smell Gas B.
• B. You will smell Gas B before you smell Gas A.
• C. You will smell Gas A but not Gas B.
• D. You will smell Gas B but not Gas A.

Correct answer: A

Rationale: The rate of effusion of a gas is inversely proportional to the square root of its molar mass. Since Gas A has twice the mass of Gas B, Gas A will effuse more slowly than Gas B. Therefore, you will likely smell Gas A before you smell Gas B as Gas A will escape and diffuse through the porous plug at a slower rate compared to Gas B. Choice A is correct because Gas A, with its higher molar mass, will take longer to effuse through the porous plug, causing you to smell it first. Choices B, C, and D are incorrect as they do not consider the relationship between molar mass and effusion rate.

2. What is the charge of noble gases?

• A. -1
• B. 0
• C. 1
• D. 2

Correct answer: B

Rationale: The correct answer is B: 0. Noble gases have a charge of 0 because they have full valence shells and are inert. This makes them stable and unreactive, resulting in a charge of 0 as they do not readily gain or lose electrons. Choices A, C, and D are incorrect because noble gases do not typically form ions by gaining or losing electrons, so they do not carry a charge of -1, 1, or 2.

3. What determines polarity in a molecule?

• A. Bond length
• B. Bond strength
• C. Electronegativity
• D. Molecular weight

Correct answer: C

Rationale: Polarity in a molecule is determined by the difference in electronegativity between the atoms forming the bond. The greater the difference in electronegativity, the more polar the bond and molecule become. This difference leads to an uneven distribution of electron density within the bond, creating partial positive and negative charges on the atoms involved. Choices A, B, and D are incorrect. Bond length and strength do not determine polarity, and molecular weight is not directly related to the polarity of a molecule.

4. What type of bond is an electrostatic attraction between two oppositely charged ions?

• A. Covalent
• B. Metallic
• C. Ionic
• D. Hydrogen

Correct answer: C

Rationale: An ionic bond forms when one atom transfers electrons to another, resulting in the formation of positively and negatively charged ions. The attraction between these oppositely charged ions creates an electrostatic bond, known as an ionic bond. Choice A, covalent bonds, involve the sharing of electrons, not the transfer. Choice B, metallic bonds, occur between metal atoms and involve a 'sea of electrons' that are delocalized. Choice D, hydrogen bonds, are much weaker interactions between hydrogen atoms and other electronegative atoms like oxygen or nitrogen.

5. Which is a triatomic allotrope of oxygen?

• A. Ozone
• B. Water
• C. Acidic oxide
• D. Carbon dioxide

Correct answer: A

Rationale: Ozone (O3) is a triatomic allotrope of oxygen. It differs from the common diatomic oxygen molecule (O2) by having three oxygen atoms bonded together. Ozone is known for its protective role in the Earth's atmosphere, absorbing most of the Sun's harmful ultraviolet radiation. Water (H2O) is a compound composed of two hydrogen atoms and one oxygen atom. Acidic oxide and carbon dioxide are not triatomic allotropes of oxygen. Carbon dioxide consists of one carbon atom and two oxygen atoms, while acidic oxides refer to compounds where oxygen is bonded with other elements to form oxides, and they are not allotropes of oxygen.

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