Nursing Elites

1. Which of the following units is used to express concentration as a mass of solute per unit volume of solution?

• A. Molality (m)
• B. Molarity (M)
• C. Weight percent (%)
• D. Parts per million (ppm)

Correct answer: A

Rationale: Molality (m) is the unit used to express concentration as a mass of solute per unit volume of solution. It is calculated by dividing the mass of solute in grams by the mass of the solvent in kilograms. Molality is preferred over molarity when there are large temperature variations as it is temperature-independent, making it a more accurate measure of concentration. Molarity (B) is the unit used to express concentration as moles of solute per liter of solution, weight percent (C) is the mass of solute per 100 parts of the total mass of the solution, and parts per million (D) is used to express very small concentrations where 1 ppm is equivalent to 1 mg of solute per liter of solution.

2. A patient's body is not properly filtering blood. Which of the following body parts is most likely malfunctioning?

• A. Medulla
• B. Heart
• C. Nephrons
• D. Renal cortex

Correct answer: C

Rationale: Nephrons are the functional units of the kidneys responsible for filtering blood and removing waste products to form urine. If a patient's body is not properly filtering blood, it is most likely due to dysfunction or impairment in the nephrons of the kidneys. The heart is responsible for pumping blood, not filtering it, making choice B incorrect. The medulla and renal cortex are specific parts of the kidney but do not directly perform the filtration function carried out by the nephrons, making choices A and D incorrect.

3. How does the Law of Conservation of Mass apply to this reaction: 2H₂ + O₂ → 2H₂O?

• A. Electrons are not lost.
• B. The hydrogen does not lose mass.
• C. New water molecules are formed.
• D. There is no decrease or increase in matter.

Correct answer: D

Rationale: The Law of Conservation of Mass states that matter cannot be created or destroyed in a chemical reaction. In the given reaction, 2 moles of hydrogen combine with 1 mole of oxygen to form 2 moles of water. The total mass of the reactants (hydrogen and oxygen) is equal to the total mass of the products (water), meaning there is no decrease or increase in matter. The total mass of the system remains constant, demonstrating the conservation of mass. Choices A, B, and C are incorrect because the conservation of mass does not specifically relate to electrons, individual elements (like hydrogen), or the formation of new molecules; instead, it focuses on the overall mass of the system before and after the reaction.

4. The pancreas releases a number of digestive enzymes into the small intestine. Which of the following enzymes is NOT produced by the pancreas?

• A. Trypsin (protein digestion)
• B. Amylase (carbohydrate digestion)
• C. Lipase (fat digestion)
• D. Lactase (sugar digestion)

Correct answer: D

Rationale: Lactase is an enzyme responsible for breaking down lactose, a sugar found in dairy products, and it is produced by the small intestine, not the pancreas. The pancreas produces enzymes like trypsin for protein digestion, amylase for carbohydrate digestion, and lipase for fat digestion. Therefore, the correct answer is D. Choices A, B, and C are incorrect because trypsin, amylase, and lipase are indeed enzymes produced by the pancreas for the digestion of proteins, carbohydrates, and fats, respectively.

5. What type of bond connects amino acids to form proteins?

• A. Covalent
• B. Peptide
• C. Ionic
• D. Hydrogen

Correct answer: B

Rationale: The correct answer is 'Peptide'. Peptide bonds are the specific type of bond that connects amino acids together to form proteins. These bonds form through a condensation reaction between the amino group of one amino acid and the carboxyl group of another amino acid, creating a covalent bond. While covalent bonds are involved in the formation of peptide bonds, the direct bond connecting amino acids in proteins is the peptide bond. Ionic bonds involve the attraction between charged particles, and hydrogen bonds are weaker bonds compared to covalent and peptide bonds, playing a different role in protein structure.

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