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 1.6 % (w/v) sodium phosphate dibasic heptahydrate solution as mOsmol per liter. The molecular weight of sodium phosphate dibasic heptahydrate is 268 g/mol


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lb equals 179.1 mOsmol/L kg

    For sodium phosphate dibasic heptahydrate , the 'golden formula' is:
    1 mmol = `[268]` mg = `[2]` mEq = `[3]` mOsmol.

    Osmolarity is the number of mOsmol in 1000 mL (1 L) of the solution.
    Using dimensional analysis:
    `(1600 \quad mg)/(100 \quad mL) × (3 \quad mOsmol)/(268 \quad mg) × (1000 \quad mL)/(1 \quad L) = 179.1 \quad (mOsmol)/(1 \quad L)`.
    Therefore, the osmolarity is 179.1. Ans.