Nursing Elites

1. What is the oxidation state of the nitrogen atom in the compound NH3?

• A. -3
• B. -1
• C. +1
• D. +3

Correct answer: B

Rationale: In the compound NH3, nitrogen is bonded to three hydrogen atoms. Hydrogen is always assigned an oxidation state of +1. Since the overall charge of NH3 is zero, the oxidation state of nitrogen must be -1 to balance out the hydrogen's +1 oxidation state. Therefore, the correct oxidation state of the nitrogen atom in NH3 is -1. Choice A (-3) is incorrect because it does not account for the electronegativity of hydrogen. Choice C (+1) and Choice D (+3) are incorrect as the nitrogen atom in NH3 needs to balance the +1 oxidation state of each hydrogen atom, resulting in a total of -3 to maintain the compound's charge neutrality.

2. What color does phenolphthalein turn in the presence of an acid?

• A. Clear
• B. Blue
• C. Pink
• D. Red

Correct answer: C

Rationale: In the presence of an acid, phenolphthalein turns pink. Phenolphthalein is a pH indicator that is colorless in acidic solutions but turns pink in basic solutions. Therefore, when added to an acidic solution, phenolphthalein will exhibit a pink coloration. Choice A, 'Clear,' is incorrect because phenolphthalein does not remain colorless in the presence of an acid. Choice B, 'Blue,' is incorrect as phenolphthalein does not turn blue in the presence of an acid. Choice D, 'Red,' is incorrect as phenolphthalein does not exhibit a red color in acidic solutions.

3. What is the SI unit of energy?

• A. ohm
• B. joule
• C. henry
• D. newton

Correct answer: B

Rationale: The SI unit of energy is the 'joule'. The joule is defined as the work done when a force of one newton acts over a distance of one meter. It is the standard unit used to measure energy in the International System of Units (SI). Therefore, the correct answer is 'joule.' Choice A, 'ohm,' is the SI unit of electrical resistance, not energy. Choice C, 'henry,' is the SI unit of inductance, not energy. Choice D, 'newton,' is the SI unit of force, not energy. Hence, they are all incorrect in the context of measuring energy.

4. What term refers to the average of the masses of each of its isotopes as they occur in nature?

• A. Atomic number
• B. Mass number
• C. Atomic mass
• D. Neutron number

Correct answer: C

Rationale: The correct answer is atomic mass. Atomic mass is the weighted average of the masses of an element's isotopes. It takes into account the abundance of each isotope in nature to provide a more accurate representation of the element's overall mass. Choice A, atomic number, represents the number of protons in an atom. Choice B, mass number, refers to the total number of protons and neutrons in an atom's nucleus. Choice D, neutron number, specifically focuses on the count of neutrons in an atom's nucleus. These choices do not directly relate to the average mass of isotopes as asked in the question.

5. What creates a dipole in a covalent bond?

• A. Unequal sharing of electrons
• B. Equal sharing of electrons
• C. Exchange of electrons
• D. Transfer of electrons

Correct answer: A

Rationale: A dipole is created in a covalent bond when there is an unequal sharing of electrons between the atoms involved. This results in a partial positive charge on one atom and a partial negative charge on the other, leading to a separation of charges and the formation of a dipole. Choices B, C, and D are incorrect because a dipole is specifically formed due to unequal sharing of electrons, not equal sharing, exchange, or transfer of electrons in a covalent bond.

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