Question

Calculate the number of chlorine atoms present in 12.46 g of CCl₄. When you have the answer, take the log (base 10) of it and enter the value with three decimal places and no units.

Answer 1

Molar mass of CCl4,

MM = 1*MM(C) + 4*MM(Cl)

= 1*12.01 + 4*35.45

= 153.81 g/mol

mass(CCl4)= 12.46 g

number of mol of CCl4,

n = mass of CCl4/molar mass of CCl4

=(12.46 g)/(153.81 g/mol)

= 8.101*10^-2 mol

number of molecules = number of mol * Avogadro’s number

number of molecules = 8.101*10^-2 * 6.022*10^23 molecules

number of molecules = 4.878*10^22 molecules

1 CCl4 Molecule has 4 atom of Cl

So,

number of Cl atoms = 4*number of molecules

= 4*4.878*10^22

= 1.95*10^23 atoms

Answer should be written in log

So, log (1.95*10^23) = 23.290

Answer: 23.290