Answer:
4777.09grams
Explanation:
To find the mass of oxygen, we first need to find the mass of potassium sulfate (K2SO4).
Since there are 4.50 x 10^25 formula units of potassium sulfate, we can find the number of moles in K2SO4 by dividing by Avagadros number (6.02 × 10^23 units). That is;
number of moles of K2SO4 (n) = 4.50 x 10^25 ÷ 6.02 × 10^23
= 0.747 × 10^ (25-23)
= 0.747 × 10^2
= 7.47 × 10^1 moles
Mass in grams of K2SO4 can be calculated thus: molar mass of K2SO4 × moles
= 174.252 g/mol × 7.47 × 10^1 moles
= 13016.62grams.
Since mass of oxygen in 1 mol of K2SO4 = O4 = 63.996 g/mol
We find the percentage by mass of oxygen in K2SO4 as follows:
= 63.996/174.252 × 100
= 0.367 × 100
= 36.7% by mass of oxygen.
This means that in 1gram of K2SO4, there are 0.367gram of Oxygen. Hence, in 13016.62grams (4.50 x 10^25 units) of K2SO4, there will be;
0.367 × 13016.62
= 4777.09grams of oxygen.
