The normal concentration of sodium chloride in blood is 0.9% (w/v). Therefore, assuming FW for Nacl of 58.4 g/mole, an isotonic 0.9% (w/v) saline would have how many milli-equivalents per liter (mEq/L) of Na ions?
Can you show me how you came up with this answer?
To determine the number of milli-equivalents per liter (mEq/L) of Na ions in an isotonic 0.9% (w/v) saline, we need to follow these steps:
Step 1: Find the molar concentration of sodium chloride (NaCl).
To do this, we start with the weight/volume percent (w/v) concentration of 0.9%. This means that for every 100 ml of the solution, we have 0.9 grams of NaCl.
Step 2: Convert grams of NaCl to moles.
To convert grams to moles, we need to know the molar mass. The formula weight (FW) for NaCl is given as 58.4 g/mol.
Using the formula:
moles = mass (g) / molar mass (g/mol)
We can calculate the number of moles of NaCl:
moles of NaCl = 0.9 g / 58.4 g/mol
Step 3: Convert moles of NaCl to millimoles of Na ions.
Since sodium chloride dissociates into one sodium ion (Na+) and one chloride ion (Cl-), the number of moles of Na ions is the same as the number of moles of NaCl.
Therefore, we have:
millimoles of Na ions = moles of Na ions = moles of NaCl
Step 4: Convert millimoles to milli-equivalents.
The milli-equivalent (mEq) is a measure of the chemical combining power of an ion. In the case of monovalent ions like sodium (Na+), the milli-equivalent is the same as millimoles.
So, milli-equivalents of Na ions = millimoles of Na ions
Finally, the 0.9% (w/v) saline solution will have the same concentration of milli-equivalents per liter (mEq/L) of Na ions as the calculated millimoles of Na ions.
Remember to check your units consistently during calculations.
0.9% NaCl w/v means 0.9g NaCl/100 mL and that is the same as 9g NaCl/L.
The equivalent weight of NaCl is the same as the formula weight of NaCl; therefore, 9/58.4 = moles NaCl/L = equivalents/L = 0.154 Eq/L or 154 mEq/L. That may not be the right number of significant figures; I don't know if that 0.9% is 0.9 or 0.900 or what. You take care of that end of it.