A doctor has ordered 40 mEq of potassium chloride by mouth. You have available a bottle labeled 10 mEq/5 ml. How many milliliters do you need to fill the order? a. 20 milliliters. b. 5 milliliters. c. 30 milliliters. d. 10 milliliters.
The Correct Answer and Explanation is :
The correct answer is a. 20 milliliters.
Explanation:
To solve this, we need to determine how many milliliters (mL) of the available potassium chloride solution are required to provide the ordered dose of 40 mEq. Here’s a step-by-step approach:
- Understand the concentration of the solution:
The concentration of the potassium chloride solution is labeled as 10 mEq/5 mL, which means that every 5 milliliters of the solution contains 10 milliequivalents (mEq) of potassium chloride. - Set up a proportion:
The goal is to find out how many milliliters of the solution are needed to deliver 40 mEq. We can set up a proportion based on the given concentration: [
\frac{10 \, \text{mEq}}{5 \, \text{mL}} = \frac{40 \, \text{mEq}}{x \, \text{mL}}
] Where x is the unknown volume (in milliliters) we need to find. - Solve the proportion:
Cross-multiply to solve for x: [
10 \, \text{mEq} \times x = 40 \, \text{mEq} \times 5 \, \text{mL}
] [
10x = 200
] [
x = \frac{200}{10} = 20 \, \text{mL}
] - Conclusion:
Therefore, you will need 20 milliliters of the solution to provide 40 mEq of potassium chloride. This corresponds to answer a. 20 milliliters.
Why This Works:
The proportion method is effective because the concentration of the solution is consistent. By using the ratio of mEq per mL and setting it equal to the desired dose, we ensure that the correct volume is calculated. The units of milliequivalents cancel out, leaving milliliters as the final unit, which is exactly what we need to measure out to fulfill the doctor’s order.