Nursing Elites

1. Which term is used to classify reactions that require light energy to proceed?

• A. Combustion reactions
• B. Endothermic reactions
• C. Photochemical reactions
• D. Double displacement reactions

Correct answer: C

Rationale: Reactions that require light energy to proceed are classified as photochemical reactions. Photochemical reactions involve the absorption of light energy to initiate a chemical reaction. Combustion reactions involve the rapid combination of a substance with oxygen, endothermic reactions absorb heat from the surroundings, and double displacement reactions involve the exchange of ions between two compounds. Therefore, the correct term for reactions requiring light energy is 'photochemical reactions,' making option C the correct answer.

2. When ice melts, it undergoes a...

• A. Chemical change
• B. Physical change
• C. Nuclear change
• D. Radioactive decay

Correct answer: B

Rationale: When ice melts, it undergoes a physical change, transitioning from a solid state to a liquid state. This change does not involve altering the chemical composition of the ice, making it a physical change rather than a chemical change, nuclear change, or radioactive decay. Choice A, 'Chemical change,' is incorrect because a chemical change involves a rearrangement of atoms resulting in new substances. Choice C, 'Nuclear change,' is incorrect as it refers to changes in the nucleus of an atom, not the phase transition of ice. Choice D, 'Radioactive decay,' is incorrect as it involves the spontaneous disintegration of an unstable atomic nucleus, which is not the process occurring when ice melts.

3. What is the process of splitting a heavy nucleus into smaller nuclei, releasing a vast amount of energy called?

• A. Nuclear fusion
• B. Nuclear fission
• C. Radioactive decay
• D. Chain reaction

Correct answer: B

Rationale: The correct answer is B: Nuclear fission. Nuclear fission is the process of splitting a heavy nucleus into smaller nuclei, releasing a vast amount of energy. This process is commonly used in nuclear power plants and nuclear weapons. It is a controlled chain reaction that generates energy. Option A, Nuclear fusion, is the process of combining two light nuclei to form a heavier nucleus, releasing energy. This process powers the sun and other stars. Option C, Radioactive decay, is the process by which an unstable atomic nucleus loses energy by emitting radiation. Option D, Chain reaction, is a self-sustaining reaction where the products of one reaction event stimulate further reaction events. While chain reactions can occur in both nuclear fission and fusion, the specific process of splitting a heavy nucleus into smaller ones is known as nuclear fission.

4. Which type of isomerism arises due to differences in the arrangement of atoms around a double bond?

• A. Chain isomerism
• B. Functional group isomerism
• C. Cis-trans isomerism
• D. Stereoisomerism

Correct answer: C

Rationale: Cis-trans isomerism, also known as geometric isomerism, arises due to differences in the arrangement of atoms around a double bond. In cis isomers, similar groups are on the same side of the double bond, while in trans isomers, similar groups are on opposite sides of the double bond. This type of isomerism is a subset of stereoisomerism, which includes all isomers that have the same connectivity but differ in spatial arrangement. Chain isomerism involves differences in the carbon chain arrangement, functional group isomerism involves different functional groups, and stereoisomerism is a broader category that encompasses isomers with the same connectivity but different spatial arrangement.

5. What is the difference between DNA and RNA?

• A. Both are double-stranded.
• B. DNA contains deoxyribose sugar, while RNA contains ribose sugar.
• C. RNA contains the nitrogenous base uracil, while DNA contains thymine.
• D. Both are identical molecules.

Correct answer: B

Rationale: A) Incorrect. DNA is double-stranded, but RNA is typically single-stranded. B) Correct. DNA contains deoxyribose sugar, which lacks an oxygen atom on the 2' carbon of the sugar ring, while RNA contains ribose sugar, which has an additional hydroxyl group on the 2' carbon. C) Incorrect. RNA contains the nitrogenous base uracil, while DNA contains thymine. D) Incorrect. DNA and RNA have distinct structures and functions, so they are not identical molecules.

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