Nursing Elites

1. What is the name for the change in enthalpy (heat) associated with a chemical reaction at constant pressure?

• A. Entropy
• B. Enthalpy
• C. Gibbs free energy
• D. Heat of reaction

Correct answer: D

Rationale: The correct answer is D, Heat of reaction. The heat of reaction, also known as the enthalpy change, is the amount of heat absorbed or released during a chemical reaction at constant pressure. Entropy (A) is a measure of the disorder or randomness of a system and is not specifically related to heat changes in a chemical reaction. Enthalpy (B) is the total heat content of a system and not just the change associated with a reaction. Gibbs free energy (C) is a measure of the energy available to do work in a system at constant temperature and pressure, but it is not the specific term for the heat change in a chemical reaction.

2. What is the purpose of genetic counseling?

• A. To treat genetic disorders.
• B. To diagnose genetic diseases in newborns.
• C. To provide information and support to individuals and families with genetic risks.
• D. To collect DNA samples for research purposes.

Correct answer: C

Rationale: The purpose of genetic counseling is to provide information and support to individuals and families with genetic risks. Genetic counselors aim to explain the implications of genetic testing, discuss risks and options, and offer emotional and psychological support to help individuals make informed decisions regarding their genetic health. Choice A is incorrect because genetic counseling is not focused on treatment but rather on providing information and support. Choice B is incorrect as genetic counselors do not primarily diagnose genetic diseases in newborns but rather provide guidance and support based on existing diagnoses. Choice D is not the purpose of genetic counseling; genetic counselors do not collect DNA samples for research purposes but instead focus on assisting individuals and families in understanding and managing their genetic risks.

3. How many moles of water are produced when 0.5 moles of methane (CH4) react with excess oxygen?

• A. 0.5 moles
• B. 1 mole
• C. 2 moles
• D. 3 moles

Correct answer: B

Rationale: The balanced chemical equation for the combustion of methane is: CH4 + 2O2 -> CO2 + 2H2O. This equation shows that 1 mole of methane produces 2 moles of water. Therefore, when 0.5 moles of methane react, they will produce 1 mole of water. The ratio of water to methane is 2:1, meaning that for every mole of methane that reacts, it produces 2 moles of water. Since only 0.5 moles of methane are reacting, the amount of water produced will be half of what would be produced if 1 mole of methane reacted, resulting in 1 mole of water being produced. Choice A is incorrect because it does not consider the stoichiometry of the reaction. Choices C and D are incorrect as they do not align with the balanced chemical equation and the stoichiometric ratios involved in the reaction.

4. Which is the correct order of formed elements in blood from smallest to largest cell size?

• A. Erythrocytes, thrombocytes, and leukocytes
• B. Thrombocytes, leukocytes, and erythrocytes
• C. Thrombocytes, erythrocytes, and leukocytes
• D. Leukocytes, erythrocytes, and thrombocytes

Correct answer: C

Rationale: The correct order of formed elements in blood from smallest to largest cell size is thrombocytes (platelets), erythrocytes (red blood cells), and leukocytes (white blood cells), making choice C the correct answer. Thrombocytes are the smallest, followed by erythrocytes, and then leukocytes. Choices A, B, and D are incorrect because they do not follow the correct order of cell size in blood formed elements.

5. In nuclear physics, the term 'barn' is a unit commonly used to quantify:

• A. Energy
• B. Radioactivity
• C. Nuclear cross-section
• D. Half-life

Correct answer: C

Rationale: In nuclear physics, the term 'barn' is a unit used to quantify nuclear cross-section. Nuclear cross-section is a measure of the probability of a nuclear reaction occurring when an atomic nucleus interacts with a particle or another nucleus. The barn is a unit of area equal to 10^-28 square meters; it is commonly used to describe the cross-sectional area of atomic nuclei for nuclear reactions. Choice A, 'Energy,' is incorrect because a barn is not a unit for measuring energy; it is a unit of area. Choice B, 'Radioactivity,' is incorrect as radioactivity is typically measured in units like becquerels. Choice D, 'Half-life,' is also incorrect as half-life is a measure of the time it takes for half of a substance to decay, not related to the concept of a barn as a unit of nuclear cross-section.

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