We know from the molecular mass that
1 mole of CCl_4 = 154 g/ mol , and we can use this information to make a conversion factor. In this case, first we are converting from grams to moles and then from moles to number of molecules.
1 mol of CCl4 has mass 154 g/mol
154 g of CCl4 makes 1 mol of CCl_4
1g of CCl_4 makes ( 1 // 154 ) moles
10.92 g of CCl_4 makes 10.92 ( 1 // 154 ) moles
10.92 g of CCl_4 makes 0.0709 moles
1 mole of CCl_4 has 6.02 x 10^ 23 molecules
0.0709 moles of CCl_4 has ( 6.02 x 10^ 23 ) x 0.0709 molecules
0.0709 moles of CCl_4 has molecules 0.426 x 10^ 23 molecules.
