dissociates into ions in a water solution

ATI RN

ATI Fluid and Electrolytes

1. Which substance dissociates into ions in a water solution?

A. Intracellular fluid
B. Interstitial fluid
C. Plasma
D. Electrolyte

Correct answer: D

Rationale: The correct answer is 'Electrolyte.' Electrolytes are substances that dissociate into ions when dissolved in water. Intracellular fluid, interstitial fluid, and plasma are not substances that dissociate into ions in a water solution. Intracellular fluid is the fluid inside cells, interstitial fluid is the fluid between cells, and plasma is the liquid component of blood. These choices do not dissociate into ions in a water solution, unlike electrolytes.

2. A nurse is assessing clients on a medical-surgical unit. Which clients are at increased risk for hypophosphatemia? (Select all that do not apply.)

A. A 36-year-old who is malnourished
B. A 42-year-old with uncontrolled diabetes
C. A 76-year-old who is prescribed antacids
D. 50-year-old with hyperparathyroidism

Correct answer: C

Rationale:

3. A nurse in the neurologic ICU has orders to infuse a hypertonic solution into a patient with increased intracranial pressure. This solution will increase the number of dissolved particles in the patient's blood, creating pressure for fluids in the tissues to shift into the capillaries and increase the blood volume. This process is best described as which of the following?

A. Hydrostatic pressure
B. Osmosis and osmolality
C. Diffusion
D. Active transport

Correct answer: B

Rationale: The correct answer is B: Osmosis and osmolality. Osmosis is the movement of fluid from a region of low solute concentration to a region of high solute concentration across a semipermeable membrane. In this case, the hypertonic solution increases the number of dissolved particles in the blood, causing fluids to shift into the capillaries due to the osmotic pressure gradient. Osmolality refers to the concentration of solutes in a solution. Hydrostatic pressure refers to changes in water or volume related to water pressure, not the movement of fluids due to solute concentration differences. Diffusion is the movement of solutes from an area of greater concentration to lesser concentration; in an intact vascular system, solutes are unable to move freely, so diffusion does not play a significant role in this scenario. Active transport involves the movement of molecules against the concentration gradient with the use of energy, typically at the cellular level, and is not related to the vascular volume changes described in the question.

4. Which of the following might the nurse assess in a patient diagnosed with hypermagnesemia?

A. Diminished deep tendon reflexes
B. Tachycardia
C. Cool clammy skin
D. Increased serum magnesium

Correct answer: A

Rationale: The correct answer is A: Diminished deep tendon reflexes. In a patient with hypermagnesemia, the nurse would assess for diminished deep tendon reflexes. Hypermagnesemia can lead to neuromuscular depression, causing a decrease in deep tendon reflexes. Tachycardia (choice B) is more commonly associated with hypomagnesemia. Cool clammy skin (choice C) is not typically a direct symptom of hypermagnesemia. While hypermagnesemia does involve increased serum magnesium levels (choice D), assessing serum levels is a laboratory test and not a clinical assessment like checking deep tendon reflexes.