Question

An aqueous solution of potassium hydroxide is mixed with an (aq) of magnesium chloride and you get a clumpy white precipitate that forms. Write a complete and balanced equation to calculate the stoichiometry question: how many grams of the precipitate are formed if 150 grams of (aq) potassium hydroxide are used as a reactant? Consider magnesium chloride to be an excess reactant that we need not quantify. Be sure to include the stat of the reactant and products in your balanced equation.

Answer 1

MgCl2(aq) + 2KOH(aq) ==> 2KCl(aq) + Mg(OH)2(s)

Here is an example stoichiometry problem worked. Just follow the steps.
http://www.jiskha.com/science/chemistry/stoichiometry.html