a 3.00-gram mixture of k2so4(s) and mnso4(s) is dissolved in water and all the sulfate is precipitated as baso4(s) by the addition of ba(no3)2(aq). if the baso4(s) precipitate has a mass of 4.37 grams, calcu- late the mass percentages of k2so4(s) and mnso4(s) in the sample.