How many grams of solid BaSO4 will form when Na2SO4 reacts with 25 mL of 0.50 M Ba(NO3)2? __ Ba(NO3)2 + __ Na2SO4  __ BaSO4 + __ NaNO3

1 Answer
Dec 14, 2014

The answer is 2.79g.

Starting from the balanced chemical equation

Ba(NO3)2(aq)+Na2SO4(aq)BaSO4(s)+2NaNO3(aq)

Taking into consideration the solubility rules (more here: http://www.chem.sc.edu/faculty/morgan/resources/solubility/), we can see that Ba(NO3)2, Na2SO4, and NaNO3 will dissociate into their respective ions, which will lead to the reaction's net ionic equation

Ba2+(aq)+SO24(aq)BaSO4(s)

Since sulfate compounds formed with Ba2+ cations are insoluble in water (only slightly soluble, BaSO4's Ksp being equal to 1.11010 ), this double-replacement reaction forms a precipitate, BaSO4.

We know from the balanced chemical equation that the mole-to-mole ratio of Ba(NO3)2 and BaSO4 is 1:1; that is, for every mole of barium nitrate used, one mole of barium sulfate is produced.

The number of barium nitrate moles can be determined from its molarity, C=nV

nBa(NO3)2=CV=0.500M25.0103L=0.012

Knowing barium sulfate's molar mass (233.3gmol), and the number of moles produced, we get

mBaSO4=nBaSO4molarmass=0.012moles233.3gmole=2.79g