Question

A student obtains a mixture of the chlorides of two unknown metals, X and Z. The percent by mass of X and the percent by mass of Z in the mixture is known. Which of the following additional information is most helpful in calculating the mole percent of XCl(s) and of ZCl(s) in the mixture?

Answer 1

Answer:

Molar masses of X and Z

Explanation:

To determine the mole percent of a mixture ( mole percent of unknown metals = number of mole of each of them divided the total of both the unknown salt × 100) since the percent by mass is know; we the molar mass of X and  Z

mole = mass given / molar mass

Answer 2

Answer:

the Molar masses of Z and X

Explanation:

The percent by mass of X states how many grams of X are in 100 grams of the mixture. Then, we know how many grams of X, Z (we also know its percent) and of Cl ( = 100 - X % - Z %). Taking 100 g of the mixture as a base, we have:

x grams of X

z grams of Z

y grams of Cl

With the molar masses of Z and X (and of Cl) we can transform all masses into moles and then compute the mole percent of XCl(s) and of ZCl(s) in the mixture