## To find out how many grams of ZnO are needed to make 6.8 g of ZnCl2, we need to follow a series of steps.

Step 1: Calculate the number of moles of ZnCl2:

To do this, we need to use the molar mass of ZnCl2, which is the sum of the atomic masses of zinc (Zn) and chlorine (Cl). The atomic mass of Zn is 65.38 g/mol, and the atomic mass of Cl is 35.45 g/mol. Adding them together, we get:

Molar mass of ZnCl2 = (1 x 65.38 g/mol) + (2 x 35.45 g/mol) = 136.28 g/mol

To convert grams of ZnCl2 to moles, we divide the mass of ZnCl2 by its molar mass:

Moles of ZnCl2 = Mass of ZnCl2 / Molar mass of ZnCl2

Moles of ZnCl2 = 6.8 g / 136.28 g/mol â‰ˆ 0.05 mol (rounded to two decimal places)

Step 2: Calculate the number of moles of ZnO:

Since the stoichiometry tells us that one mole of ZnO is needed to make one mole of ZnCl2, the number of moles of ZnO required is the same as the number of moles of ZnCl2:

Moles of ZnO = 0.05 mol

Step 3: Calculate the mass of ZnO:

To convert moles of ZnO to grams, we need to use the molar mass of ZnO. The molar mass of ZnO is the sum of the atomic masses of zinc (Zn) and oxygen (O). The atomic mass of Zn is 65.38 g/mol, and the atomic mass of O is 16.00 g/mol. Adding them together, we get:

Molar mass of ZnO = (1 x 65.38 g/mol) + (1 x 16.00 g/mol) = 81.38 g/mol

To calculate the mass of ZnO, we multiply the number of moles of ZnO by its molar mass:

Mass of ZnO = Moles of ZnO x Molar mass of ZnO

Mass of ZnO = 0.05 mol x 81.38 g/mol â‰ˆ 4.07 g (rounded to two decimal places)

Therefore, approximately 4.07 grams of ZnO is needed to make 6.8 grams of ZnCl2.