in the reaction 2na 2h2o 2naoh h2 what is the limiting reactant when 3 moles of sodium react with 2 moles of water

ATI TEAS 7

TEAS 7 science quizlet

1. In the reaction 2Na + 2H2O → 2NaOH + H2, what is the limiting reactant when 3 moles of sodium react with 2 moles of water?

A. Na
B. H2O
C. NaOH
D. H2

Correct answer: A

Rationale: The balanced chemical equation indicates that 2 moles of sodium react with 2 moles of water to yield 2 moles of sodium hydroxide and 1 mole of hydrogen gas. When 3 moles of sodium react with only 2 moles of water, sodium becomes the limiting reactant as it is present in excess compared to the available water molecules. This situation arises because not all sodium atoms can fully react with the limited amount of water, resulting in sodium being the limiting reactant in this specific case. Choice B (H2O), choice C (NaOH), and choice D (H2) are incorrect as they are not the limiting reactant in the given reaction scenario.

2. During antibiotic use, bacteria can evolve resistance. This is an example of:

A. Coevolution (two species influencing each other's evolution)
B. Convergent evolution (unrelated organisms evolving similar traits)
C. Macroevolution (large-scale evolutionary change)
D. Artificial selection acting on a natural process

Correct answer: D

Rationale: The process of bacteria evolving resistance to antibiotics due to the selective pressure exerted by the antibiotics is an example of artificial selection (human intervention selecting for certain traits) acting on a natural process (bacterial evolution). Antibiotic use creates a selective pressure that favors the survival and reproduction of bacteria with resistance traits, leading to the evolution of antibiotic-resistant strains. - Coevolution (option A) refers to the influence of two species on each other's evolution, which is not the case in the scenario described in the question. - Convergent evolution (option B) involves unrelated organisms evolving similar traits due to similar environmental pressures, which is not directly applicable to the situation of bacteria evolving resistance to antibiotics. - Macroevolution (option C) refers to large-scale evolutionary changes over long periods, which is not specifically demonstrated in the context of bacteria evolving resistance during antibiotic use.

3. Which of the following is a chief difference between evaporation and boiling?

A. Liquids boil only at the surface, while they evaporate equally throughout the liquid.
B. Evaporating substances change from liquid to gas, while boiling substances change from gas to liquid.
C. Evaporation can happen below a liquid's boiling point.
D. Evaporation happens in nature, while boiling is a man-made phenomenon.

Correct answer: C

Rationale: The chief difference between evaporation and boiling is that evaporation can happen below a liquid's boiling point, while boiling only occurs at the liquid's boiling point. Evaporation is the process of a liquid turning into a gas at any temperature, while boiling specifically refers to the rapid vaporization that occurs when a liquid reaches its boiling point. Choice A is incorrect because liquids evaporate throughout the liquid, not just at the surface. Choice B is incorrect as evaporating substances change from liquid to gas, while boiling substances change from liquid to gas. Choice C is incorrect as boiling is not a man-made phenomenon; in fact, it is a natural process based on temperature changes. Choice D is incorrect because evaporation can happen naturally and is not limited to man-made processes.

4. Which of the following statements regarding the pericardium is not correct?

A. It allows for the heart to work in a relatively friction-free environment
B. It is a single-walled layer around the heart
C. It prevents overfilling of the heart with blood
D. It protects and anchors the heart

Correct answer: B

Rationale: The correct statement about the pericardium is that it is double-walled, not single-walled. Choice A is correct because the pericardium does allow the heart to work in a relatively friction-free environment, reducing friction during heartbeats. Choice C is correct as the pericardium helps prevent the overfilling of the heart with blood. Choice D is also correct as the pericardium serves to protect and anchor the heart in place within the chest cavity.

5. Which of the following factors does not strengthen a scientific argument?

A. Lack of bias
B. Extensive use of qualitative research and data
C. Able to be reproduced and repeated by others
D. Withstands the test of time

Correct answer: B

Rationale: The correct answer is B. While qualitative data can provide valuable insights, it does not inherently strengthen a scientific argument to the same extent as quantitative data. Quantitative data is generally more precise, measurable, and easier to verify, making it a stronger basis for scientific arguments. Choices A, C, and D all contribute to strengthening a scientific argument. Lack of bias ensures objectivity and reliability, reproducibility by others validates the findings, and standing the test of time indicates the enduring validity and reliability of the argument.