What is the concentration in mmol/L of a Ca2+ solution that is 2.50 meq/L?
The Correct Answer and Explanation is:
To convert the concentration of Ca²⁺ from milliequivalents per liter (meq/L) to millimoles per liter (mmol/L), we need to account for the valence of calcium ions (Ca²⁺).
Step-by-step Conversion Process:
- Understanding Milliequivalents (meq):
A milliequivalent (meq) is a measure of the chemical reactivity of an ion. For an ion like Ca²⁺, the milliequivalent value depends on its charge. For calcium, which has a charge of +2, the relation between moles, equivalents, and charge is: 1 eq=1 mol of charge=2 mol of Ca²⁺(since Ca²⁺ has a charge of +2)1 \, \text{eq} = 1 \, \text{mol of charge} = 2 \, \text{mol of Ca²⁺} \quad (\text{since Ca²⁺ has a charge of +2})1eq=1mol of charge=2mol of Ca²⁺(since Ca²⁺ has a charge of +2) Therefore, 1 mole of Ca²⁺ corresponds to 2 equivalents. - Conversion between meq and mmol:
We know that 1 milliequivalent (meq) equals 1/1000 of an equivalent, and 1 millimole (mmol) equals 1/1000 of a mole. Since 1 equivalent of Ca²⁺ corresponds to 1/2 mole (because of the +2 charge), the conversion from meq to mmol for Ca²⁺ involves dividing the meq value by the valence (which is 2 for Ca²⁺). - Calculation:
Given that the concentration of the Ca²⁺ solution is 2.50 meq/L, to convert this to mmol/L, we use the formula: mmol/L=meq/Lvalence of Ca²⁺\text{mmol/L} = \frac{\text{meq/L}}{\text{valence of Ca²⁺}}mmol/L=valence of Ca²⁺meq/L So, we have: mmol/L=2.50 meq/L2=1.25 mmol/L\text{mmol/L} = \frac{2.50 \, \text{meq/L}}{2} = 1.25 \, \text{mmol/L}mmol/L=22.50meq/L=1.25mmol/L
Final Answer:
The concentration of the Ca²⁺ solution is 1.25 mmol/L.
Explanation:
The conversion hinges on understanding the valence of the ion in question. Since calcium (Ca²⁺) has a charge of +2, we divide the milliequivalent value by 2 to find the millimole concentration. The value of 1.25 mmol/L is the equivalent concentration of Ca²⁺ ions in the solution, meaning for every liter of solution, there are 1.25 millimoles of Ca²⁺ ions present.
