Nursing Elites

1. Which type of radiation emits helium ions and can be stopped by a piece of paper?

• A. Beta radiation
• B. Alpha radiation
• C. Gamma radiation
• D. X-ray radiation

Correct answer: B

Rationale: Alpha radiation emits helium ions, which are helium nuclei without electrons, making them positively charged. These ions are relatively large and heavy compared to beta and gamma radiation. Due to their size and charge, alpha particles interact strongly with matter and are easily stopped. A piece of paper or even human skin can effectively block alpha radiation. Therefore, alpha radiation is the type of radiation that can be stopped by a piece of paper. Beta radiation consists of fast-moving electrons and can penetrate further into materials than alpha radiation, thus not stopped by a piece of paper. Gamma radiation is highly penetrating and requires dense materials like lead or concrete to block it effectively. X-ray radiation, similar to gamma radiation, is also highly penetrating and cannot be stopped by a piece of paper.

2. How does increasing the concentration of reactants affect a chemical reaction?

• A. Decreases the reaction rate
• B. Increases the reaction rate
• C. Stops the reaction
• D. Has no effect

Correct answer: B

Rationale: Increasing the concentration of reactants leads to more reactant particles being available, which, in turn, increases the likelihood of successful collisions between particles. This higher frequency of collisions results in a higher reaction rate. Therefore, option B, 'Increases the reaction rate,' is the correct answer. Choice A, 'Decreases the reaction rate,' is incorrect because higher reactant concentration usually speeds up the reaction. Choice C, 'Stops the reaction,' is incorrect as increasing concentration promotes more collisions, enhancing the reaction. Choice D, 'Has no effect,' is incorrect because changing reactant concentration directly impacts the reaction rate in most cases.

3. How are elements arranged in the periodic table?

• A. By their atomic mass
• B. By their chemical properties
• C. By their physical state
• D. By their charge

Correct answer: B

Rationale: Elements are arranged in the periodic table based on their chemical properties, making choice B the correct answer. The periodic table is organized so that elements with similar chemical properties are grouped together in columns, known as groups or families. This arrangement allows for the identification of trends in the behavior of elements and predicting their properties based on their position in the table. Choices A, C, and D are incorrect because the periodic table primarily focuses on the chemical properties of elements, not solely on atomic mass, physical state, or charge.

4. Identify the type of reaction shown: 8Fe + S → 8FeS

• A. Single displacement
• B. Double displacement
• C. Synthesis
• D. Acid-base

Correct answer: C

Rationale: The reaction shown (8Fe + S → 8FeS) is a synthesis reaction. In a synthesis reaction, two or more substances combine to form a single compound. In this case, iron (Fe) and sulfur (S) combine to form iron sulfide (FeS). The key characteristic of a synthesis reaction is the formation of a single product from multiple reactants, which aligns with the given chemical equation. Choice A, single displacement, involves an element displacing another in a compound, which is not the case here. Choice B, double displacement, involves the exchange of ions between two compounds, which is also not happening in this reaction. Choice D, acid-base, refers to reactions between an acid and a base to form salt and water, which is not the case in the given equation.

5. Here are the solubilities of four substances at 0°C, in grams of solute per 100 mL of water. If the temperature increases to 20°C, what would you expect to happen to the solubility figures?

• A. Citric acid and potassium phosphate will decrease; nitrogen and oxygen will increase.
• B. Citric acid and potassium phosphate will increase; nitrogen and oxygen will decrease.
• C. All four figures will increase.
• D. All four figures will decrease.

Correct answer: C

Rationale: Solubility generally tends to increase with temperature for most solid solutes in liquid solvents due to higher kinetic energy leading to better solute-solvent interactions. As the temperature increases from 0°C to 20°C, all four solubility figures are expected to increase. Choice A is incorrect because solubility tends to increase with temperature. Choice B is incorrect as well for the same reason. Choice D is incorrect because the solubility of solid solutes typically increases with temperature.

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