calculation of mEq from conc
 

a medical textbook says "10 ml of 5% magnesium sulphate (MgSO4) provides about 4 mEq Magnesium"-- my calculation says it should be 8 mEq. i am flabergasted. also at the fag end of my knowledge in chem as i am studying medicine and followed by specialization in psychiatry for last 12 years. somebody please help.
debabrata

the amount of equivalents is the amount of mols multiplied with the coefficient of the ionspecies mulitplied with the carge of the ion.

5% = 5g / 100 mL --> thus 10 mL contains 0,5 g MgSO4

--> 0,5 g MgSO4 is equal to 4,2 mmol

--> this is equal to 4,2 * 1 * 2 = 8,4 mEq MgSO4 (1 for the ionspecies Mg and 2 for the 2+-charge of Mg)

You didn't bring the charge into account ;)