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1. A nurse is preparing a solution of 0.9% sodium chloride (NaCl) to administer intravenously to a patient.
How many grams of NaCl are needed to make 500 mL of this solution?
a) 4.5 g
b) 9 g
c) 45 g
d) 90 g
Answer: A
Rationale: The mass percent of a solution is the mass of solute divided by the mass of solution times .
In this case, the mass percent of NaCl is 0.9%, which means that for every 100 g of solution, there are 0.9
g of NaCl. To find the mass of NaCl needed for 500 mL of solution, we can use a proportion: 0.9 g / 100 g
= x g / 500 g, where x is the unknown mass of NaCl. Solving for x, we get x = 0.9 g x 500 g / 100 g = 4.5
g.
2. A nurse is measuring the blood glucose level of a patient using a glucometer. The glucometer displays
the result in milligrams per deciliter (mg/dL). The normal range of blood glucose is 70 to 140 mg/dL. The
patient's result is 180 mg/dL. What is the blood glucose level of the patient in millimoles per liter
(mmol/L), which is another common unit used in medicine?
a) 3.6 mmol/L
b) 7.2 mmol/L
c) 10 mmol/L
d) 18 mmol/L
Answer: C
Rationale: To convert from mg/dL to mmol/L, we need to know the molecular weight of glucose, which is
C6H12O6. The molecular weight of glucose is the sum of the atomic weights of its constituent elements: C
= 12 g/mol, H = 1 g/mol, O = 16 g/mol. Therefore, the molecular weight of glucose is 6 x 12 + 12 x 1 + 6 x
16 = 180 g/mol. This means that one mole of glucose has a mass of 180 g, and one millimole of glucose
has a mass of 0.18 g. To convert from mg/dL to mmol/L, we need to divide by the molecular weight in
mg/mmol and multiply by the conversion factor from dL to L: mg/dL / (180 mg/mmol) x (10 dL/L) =
mmol/L. In this case, the blood glucose level of the patient is 180 mg/dL / (180 mg/mmol) x (10 dL/L) =
10 mmol/L.
3. A nurse is administering a drug to a patient that inhibits the enzyme catalase, which catalyzes the
decomposition of hydrogen peroxide (H2O2) into water (H2O) and oxygen (O2). What type of chemical
reaction is this and what will be the effect of the drug on the reaction rate?
a) Synthesis reaction; the drug will increase the reaction rate
b) Synthesis reaction; the drug will decrease the reaction rate
c) Decomposition reaction; the drug will increase the reaction rate
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