HEY THERE
THATS EASY...
YOU CAN USE A MAGNET TO ATTRACT THE IRON FILLINGS WHICH WOULD THEN SEPARATE FROM THE SAND.
<u>Answer:</u> 6 moles of 
will be decomposed.
<u>Explanation:</u>
We are given:
Moles of oxygen gas produced = 9 moles
The chemical equation for the decomposition of follows:
By the stoichiometry of the reaction:
If 3 moles of oxygen gas is produced by 2 moles of
So, 9 moles of oxygen gas will be produced by = 
of
Hence, 6 moles of will be decomposed.
I am going to assume that the reaction occurs in water since that is the easiest procedure (let me know if I am not supposed to make this assumption).
1) get 2 beakers, the chemicals for the reaction, DI water, and the catalyst.
2) equal volumes and amounts of the water was placed into the 2 beakers.
3) some of the catalyst was added to beaker the second beaker.
3) equal amounts of the chemicals for the reaction was placed into the 2 beakers.
4) the two reactions were compared to see how the un-catalyzed reaction in beaker 1 was effected by the introduction of a catalyst in beaker 2.
I hope this helps. Let me know in the comments if anything was unclear.
