KCl mEq to percent strength conversion.
The Correct Answer and Explanation is :
To convert potassium chloride (KCl) from milliequivalents (mEq) to percent strength, we need to understand the relationship between the two units and use the molecular weight of KCl.
Conversion Process:
- Understand the units:
- mEq (milliequivalent): A measure of the amount of substance based on its chemical reactivity, specifically the amount of substance that can provide or react with one millimole of hydrogen ions (H⁺).
- Percent strength: The mass of the solute (KCl) as a percentage of the total solution volume.
- Molecular weight of KCl:
- Potassium chloride (KCl) consists of potassium (K) and chloride (Cl).
- The atomic weight of potassium (K) is approximately 39.1 g/mol, and for chlorine (Cl), it is about 35.5 g/mol.
- The molecular weight of KCl = 39.1 g/mol + 35.5 g/mol = 74.6 g/mol.
- Convert mEq to grams:
- 1 mEq of KCl corresponds to 1 millimole of K⁺, which is the same as 1 millimole of KCl (since KCl dissociates into K⁺ and Cl⁻ in solution).
- 1 millimole of KCl weighs 74.6 milligrams (mg), so 1 mEq of KCl = 74.6 mg.
- Convert grams to percent strength:
- Percent strength is calculated as the mass of solute (in grams) divided by the total volume of the solution (in milliliters) and multiplied by 100.
- For a solution, if we have a certain number of mEq of KCl per mL, we can convert this to grams, and then to percent strength.
Example Conversion:
If you have a solution containing 20 mEq of KCl in 100 mL of solution:
- First, convert 20 mEq to grams:
- 20 mEq × 74.6 mg/mEq = 1492 mg = 1.492 grams of KCl.
- Now, calculate the percent strength:
- Percent strength = (1.492 grams / 100 mL) × 100 = 1.492% KCl.
Thus, a 20 mEq/100 mL solution of KCl is a 1.492% KCl solution.