What is the concentration of each ion in 5.00L of a 1.25M solution of Fe2(CO3)3?

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gsenviro | College Teacher | (Level 1) Educator Emeritus

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There are two ions in ferric carbonate salt: ferric ion or Fe(III) ion and carbonate ion.

Given volume of salt = 5 lt

And concentration of salt = 1.25 M

Concentration is given as moles per liter or M. In ferric carbonate, there are 2 moles for every mole of salt. That is, 1.25 M salt contains 2 x 1.25 = 2.5 M ferric ion. 

Similarly, each mole of salt contains 3 moles of carbonate ion. Thus, 1.25 M salt contains 3 x 1.25 M = 3.75 M carbonate ions. 

Remember that concentration is not a function of how many liters of salt there is, that is, it is independent of the quantity of salt. 1 ml of salt can have the same concentration as 10 lt of it. 

We can calculate the moles of each ion using the given volume. For 5 lt of salt containing 2.5 M ferric ion, there are 5 x 2.5 moles = 12.5 moles of ferric ion. Similarly, there are 18.75 moles of carbonate ions.

Hope this helps.