Nokea
What happens to the concentration of hydrogen ions (\([H^+]\)) in a solution as the pH increases?
- A. Increases
- B. Decreases
- C. Remains constant
- D. Becomes neutral
Correct Answer: B
Rationale: As the pH increases, the concentration of hydrogen ions decreases. The relationship is inversely proportional
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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.
During vigorous exercise, why does the respiratory rate increase?
- A. Meet the increased demand for oxygen in working muscles
- B. Eliminate excess carbon dioxide more slowly
- C. Conserve energy for physical activity
- D. Decrease the amount of oxygen delivered to the body
Correct Answer: A
Rationale: During vigorous exercise, the muscles require more oxygen to produce energy for physical activity. The increased respiratory rate helps to deliver more oxygen to the working muscles to meet this demand. This process is essential for sustaining physical activity and preventing fatigue. Choice A is the correct answer as it accurately describes the purpose of the increased respiratory rate during vigorous exercise. Choices B, C, and D are incorrect. Choice B, 'Eliminate excess carbon dioxide more slowly,' is inaccurate as the primary reason for the increased respiratory rate during exercise is to meet the increased demand for oxygen, not to eliminate carbon dioxide. Choice C, 'Conserve energy for physical activity,' is incorrect because increasing the respiratory rate actually expends energy to meet the oxygen demand of the working muscles. Choice D, 'Decrease the amount of oxygen delivered to the body,' is incorrect as the increased respiratory rate is specifically to deliver more oxygen to the body during exercise.
What phenomenon occurs when a wave encounters a change in medium causing a change in its speed and direction?
- A. Refraction
- B. Reflection
- C. Diffraction
- D. Interference
Correct Answer: A
Rationale: Refraction is the phenomenon that occurs when a wave encounters a change in medium, causing a change in its speed and direction. This change in speed and direction is due to the wave bending as it passes from one medium to another with a different density. It is essential to understand refraction as it plays a crucial role in various phenomena, such as the bending of light in lenses, the formation of rainbows, and the way seismic waves travel through the Earth's layers. Reflection, while also a wave phenomenon, involves the bouncing back of a wave when it encounters a boundary. Diffraction refers to the bending of waves around obstacles or through openings, and interference involves the combination of two or more waves to form a new wave pattern.
What is the primary organ responsible for filtering urine?
- A. Kidneys
- B. Bladder
- C. Ureters
- D. Urethra
Correct Answer: A
Rationale: The correct answer is A: Kidneys. The kidneys are the primary organs responsible for filtering urine. They filter waste products and excess substances from the blood to produce urine. Subsequently, urine travels from the kidneys through the ureters to the bladder. The bladder temporarily stores urine until it is expelled from the body through the urethra. The bladder's function is storage, the ureters transport urine, and the urethra is the exit pathway for urine expulsion. Therefore, the kidneys play a vital role in the filtration and production of urine within the urinary system.
What is the largest lymphatic vessel in the body?
- A. Jugular vein
- B. Thoracic duct
- C. Subclavian vein
- D. Aorta
Correct Answer: B
Rationale: The thoracic duct is the largest lymphatic vessel in the body, responsible for draining lymph from most parts of the body except for the right upper quadrant. The jugular vein, subclavian vein, and aorta are not part of the lymphatic system; they are blood vessels and do not serve as lymphatic vessels. Therefore, choices A, C, and D are incorrect as they are not associated with the lymphatic system's transport of lymph.