Nursing Elites

1. What is the name of the compound CH₃-CH₂-CH₂-CH₃?

• A. Cyclobutane
• B. Butane
• C. Butene
• D. Butyne

Correct answer: B

Rationale: The compound CH₃-CH₂-CH₂-CH₃ is named butane. Butane is a straight-chain alkane comprising four carbon atoms connected by single bonds. The prefix 'but-' denotes the presence of four carbon atoms, while the suffix '-ane' indicates it is an alkane with single bonds between the carbon atoms. Choice A, Cyclobutane, is incorrect as it refers to a cyclic hydrocarbon with four carbon atoms in a ring structure. Choice C, Butene, is incorrect because it is an alkene with a double bond between two carbon atoms, not a saturated hydrocarbon like butane. Choice D, Butyne, is also incorrect as it is an alkyne with a triple bond between two carbon atoms, unlike the single bonds in butane.

2. What are the products of the combustion of a hydrocarbon?

• A. Water and carbon dioxide
• B. Water and oxygen
• C. Hydrogen and carbon monoxide
• D. Carbon dioxide and oxygen

Correct answer: A

Rationale: When a hydrocarbon undergoes combustion, it reacts with oxygen to produce water and carbon dioxide as the main products. The general chemical equation for the combustion of a hydrocarbon is hydrocarbon + oxygen → carbon dioxide + water. Therefore, the correct answer is 'Water and carbon dioxide.' Choices B, C, and D are incorrect because water and carbon dioxide are the primary products of hydrocarbon combustion, not water and oxygen, hydrogen and carbon monoxide, or carbon dioxide and oxygen.

3. How many neutrons does carbon-14 have?

• A. 10
• B. 8
• C. 6
• D. 12

Correct answer: B

Rationale: The correct answer is B: 8. Carbon-14 is an isotope of carbon with 6 protons and 8 neutrons. To determine the number of neutrons in an atom, subtract the atomic number (number of protons) from the mass number. In this case, the mass number of carbon-14 is 14, and the atomic number of carbon is 6. Therefore, 14 (mass number) - 6 (atomic number) = 8 neutrons. Choices A, C, and D are incorrect because they do not reflect the correct number of neutrons in a carbon-14 atom.

4. 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.

5. Which law states that matter can neither be created nor destroyed during a chemical reaction?

• A. Law of Conservation of Energy
• B. Law of Conservation of Mass
• C. Law of Constant Composition
• D. Law of Multiple Proportions

Correct answer: B

Rationale: The correct answer is B, the Law of Conservation of Mass. This law, formulated by Antoine Lavoisier, states that matter cannot be created or destroyed in a chemical reaction. It is a fundamental principle in chemistry that explains the preservation of mass during chemical reactions, indicating that the total mass of the reactants is equal to the total mass of the products. The other choices are incorrect because: A: The Law of Conservation of Energy states that energy cannot be created or destroyed, not matter. C: The Law of Constant Composition refers to compounds having the same composition by mass regardless of their source or how they were prepared, not about the conservation of matter in reactions. D: The Law of Multiple Proportions describes the ratios in which elements combine to form compounds, not the conservation of mass.

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