Question

Metal vapor deposition is a process used to deposit a very thin layer of metal on a target substrate. A researcher puts a glass slide in the metal vapor deposition chamber and coats the slide with zirconium. After deposition, the glass slide had increased in mass by 1.94 milligrams. Approximately how many zirconium atoms were deposited on the glass slide?

Answer 1

Zirconium (Zr) has a molar mass of 91.224 g/mol

mass of Zr deposited = 1.94 mg = 1.94 x 10^-3 g

moles of Zr deposited = (mass of Zr deposited) / (molar mass of Zr)

moles of Zr deposited = (1.94 x 10^-3 g) / (91.224 g/mol)

moles of Zr deposited = 2.13 x 10^-5 mol

atoms of Zr deposited = (moles of Zr deposited) * (Avagadro's number)

atoms of Zr deposited = (2.13 x 10^-5 mol) * (6.022 x 10²³ atoms/mol)

atoms of Zr deposited = 1.28 x 10¹⁹ atoms