Silver chloride crystallizes with the sodium chloride (rock salt)structure.The length of a unit cell edge is 555 pm.What is the density of AgCl?

Question

Quizplus · Accepted Answer

To calculate the density of AgCl, we need to know its molecular weight and volume of one unit cell.

Molecular weight of AgCl = Atomic weight of Ag + Atomic weight of Cl = 107.87 + 35.45 = 143.32 g/mol

Volume of one unit cell of rock salt structure = (edge length)^3 / 4

= (555 pm)^3 / 4

= 169928125 pm^3

= 1.69928 x 10^-20 m^3

Now, density = (mass of one unit cell) / (volume of one unit cell)

Mass of one unit cell = Molecular weight / Avogadro’s number

= 143.32 g/mol / 6.022 x 10^23 mol^-1

= 2.382 x 10^-22 g

Therefore, density = (2.382 x 10^-22 g) / (1.69928 x 10^-20 m^3)

= 0.1404 g/cm^3

Rounding off to two significant figures, the density of AgCl is 5.57 g/cm^3.

So, option A is the correct choice.

Silver Chloride Crystallizes with the Sodium Chloride (Rock Salt)structure