Type 1: Determine mOsmol from weight or percent of the solute

5. mEq and mOsmol 5.2) mOsmol 5.2.1) mOsmol - General

5.2.1.1) mOsmol - General Normal 1


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Express the concentration of 0.5 % (w/v) monobasic sodium phosphate solution as mOsmol per liter. The molecular weight of monobasic sodium phosphate is 119.98 g/mol


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lb equals 83.35 mOsmol/L kg

    For monobasic sodium phosphate , the 'golden formula' is:
    1 mmol = `[119.98]` mg = `[1]` mEq = `[2]` mOsmol.

    Osmolarity is the number of mOsmol in 1000 mL (1 L) of the solution.
    Using dimensional analysis:
    `(500 \quad mg)/(100 \quad mL) × (2 \quad mOsmol)/(119.98 \quad mg) × (1000 \quad mL)/(1 \quad L) = 83.35 \quad (mOsmol)/(1 \quad L)`.
    Therefore, the osmolarity is 83.35. Ans.