Answer:
57.6g
Step-by-step explanation:
In the balanced equation H2O and Mg(OH)2 have the same coefficient (1) so we know that 3.2 moles of H2O react to form 3.2 moles of Mg(OH)2. Now we just have to calculate the mass of the H2O which we can do by finding the molar mass from the periodic table. For this just add the molar masses of the consituent atoms. (2(1)+1(16))=18g/mol H2O. Now that we know the molar mass we just have to multiply it by the amount of moles. 18*3.2=57.6g H2O