a solid mixture weighs 0.206 g. it contains gallium bromide (gabr3) and other inert impurities. when the solid mixture was dissolved in water and treated with excess silver nitrate (agno3), 0.106 g of agbr was precipitated. a balanced chemical equation describing the reaction is provided below. gabr3(aq) + 3 agno3(aq) ⟶ 3 agbr(s) + ga(no3)3(aq) what is the percent of mass of gabr3 in the solid mixture?