Question

Stoichiometry:
A student is given 2.94g of a mixture containing an hydrous MgCl2 and KNO3. To determine the percentage by the mass of MgCl2 in the mixture, the student uses excess AgNO3(aq) to precipitate the chloride ion as AgCl(s). The student determines the mass of AgCl precipitate to be 5.48g. On the basis of this information, calculate each of the following.

A) The number of moles of MgCl2 in the original mixture

B) The percent by mass of MgCl2 in the original mixture