To determine the number of molecules of Cl2 in 14.2 g of the substance, we need to use the following steps:
1.) Calculate the number of moles of Cl2 in 14.2 g using its molar mass.
2.)Use Avogadro's number to convert moles to molecules.
The molar mass of Cl2 is 70.9 g/mol (35.45 g/mol x 2), so:
1.) Number of moles of Cl2 = mass / molar mass = 14.2 g / 70.9 g/mol = 0.2 mol
2.) Number of molecules of Cl2 = number of moles x Avogadro's number
= 0.2 mol x 6.022 x 10^23 molecules/mol
= 1.204 x 10^23 molecules
Therefore, there are approximately 1.204 x 10^23 molecules of Cl2 in 14.2 g of this substance.
easy