posted by amanda .
A solution contains an unknown amount of dissolved magnesium (Mg 2+). Addition of 5.50×10^−2 mol of Na2CO3 causes complete precipitation of all of the magnesium. what mass of the magnesium was dissolved in the solution? answer in unit g.
First write and balance the equation.
Mg^+2 + Na2CO3 ==> 2Na^+ + MgCO3.
You know how many moles Na2CO3 were used. Convert mole Na2CO3 to moles Mg using the coefficients in the balanced equation. Then convert moles Mg to grams. g = moles x molar mass.