Nursing Elites

1. In the reaction 4Al + 3O2 → 2Al2O3, what is the mole ratio of aluminum to oxygen?

• A. 4:3
• B. 2:3
• C. 3:2
• D. 3:4

Correct answer: a

Rationale: The coefficients in the balanced equation represent the mole ratio, which is 4 moles of Al to 3 moles of O2.

2. The free edges of your fingernails and toenails are technically called the:

• A. Lunula (The lunula is the white crescent moon shape at the base of the nail)
• B. Matrix (The matrix is the area under the nail where new nail cells are produced)
• C. Hyponychium (This is the skin under the free edge of the nail)
• D. Free edge

Correct answer: D

Rationale: The free edges of your fingernails and toenails are the parts that extend beyond the fingertip or toe. These edges are commonly referred to simply as the "free edge" because they are not attached to the skin. The lunula is the white crescent moon shape at the base of the nail, the matrix is the area under the nail where new nail cells are produced, and the hyponychium is the skin under the free edge of the nail. Therefore, the correct answer is D.

3. A balanced chemical equation for the reaction between sodium and chlorine to form sodium chloride is:

• A. Na + Cl2 -> NaCl
• B. 2Na + Cl2 -> 2NaCl
• C. Na2 + Cl -> 2NaCl
• D. Na + 2Cl -> NaCl2

Correct answer: A

Rationale: The correct balanced chemical equation for the reaction between sodium and chlorine to form sodium chloride is '2Na + Cl2 -> 2NaCl'. This equation is balanced as it shows that 2 atoms of sodium react with 1 molecule of chlorine gas to produce 2 molecules of sodium chloride. Option A 'Na + Cl2 -> NaCl' is incorrect as it does not balance the number of atoms on both sides of the equation. It only shows 1 atom of sodium reacting with 1 molecule of chlorine, which is not a balanced representation of the chemical reaction. Therefore, option B is the correct choice for this question.

4. Electrons occupy specific energy levels around the nucleus with varying probabilities. The electron cloud model depicts electrons existing in distinct energy levels, not fixed orbits, with probabilities of finding them in specific regions.

• A. 2 protons and 6 neutrons
• B. 2 filled s orbitals and 6 filled p orbitals
• C. 2s orbitals with 2 and 6 electrons, respectively
• D. 4 filled electron shells

Correct answer: B

Rationale: 2 filled s orbitals and 6 filled p orbitals. This notation indicates two electrons in the 2s orbital and six electrons in the 2p orbitals.

5. What is the name for the tiny particles that make up atoms?

• A. Protons
• B. Electrons
• C. Neutrons
• D. Subatomic particles

Correct answer: D

Rationale: Protons, neutrons, and electrons are all subatomic particles that make up atoms.

6. How does the stability of an atom's nucleus influence its radioactive decay?

• A. Stable nuclei never undergo radioactive decay.
• B. Unstable nuclei are more likely to decay through various processes.
• C. Decay releases energy, making stable nuclei more prone to it.
• D. The element's position on the periodic table determines its decay rate.

Correct answer: B

Rationale: Unstable nuclei are more likely to decay through various processes. The stability of an atom's nucleus is a key factor in determining whether it will undergo radioactive decay. Unstable nuclei have an excess of either protons or neutrons, leading to an imbalance in the nucleus. To achieve a more stable configuration, these nuclei will undergo radioactive decay by emitting particles or energy. Stable nuclei, on the other hand, are less likely to undergo radioactive decay as they have a balanced number of protons and neutrons.

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