Explanation:
The given data is as follows.
Mass of a lead atom = 
Volume = 2.00 
Density = 11.3 
As it is mentioned that 1 cubic centimeter contains 11.3 grams of lead.
So, in 2 cubic centimeter there will be
of lead atoms.
One lead atom has a mass of
. Therefore, number of atoms present in 22.6 g of lead will be as follows.

= 
Thus, we can conclude that there are
of lead are present.
There is 118 elements<span> in the periodic table</span>
It should be for the total solution of 93 plus 20 grams which is 113 grams so 93 divided by 113 grams comes to 82.3% sodium sulfate and this can be checked by multiplying 113 grams by 0.823 which results in 93 grams of sodium sulphate.
Formula: NA2S2O3. Valency: 2