Answer:
0.533 mol O2
Explanation:
4 Fe3O4 + O2 -> 6 Fe2O3
1 mol O2 -> 6 mol Fe2O3
x -> 3.2 mol Fe2O3
x = (3.2 mol Fe2O3 * 1 mol O2)/ 6 mol Fe2O3
x= 0.533 mol O2
Answer:
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Explanation:
The half life of a substance is the time taken by a radioactive substance to decay by half its original mass. In this case, the half life of Potassium-40 is 1.3 billion years.
Original mass of Potassium-40 = 12 g (100%)
New mass after the decay = 3 g ( 25 %, since 75% was replaced by argon)
New mass = Original mass × (1/2)^n ; where n is the number of half lives.
3 = 12 × (1/2)^n
(1/2)^n = 1/4
n = 2
Therefore; the time taken will be 1.3 × 2 = 2.6 Billion years
