The concentration of a substance involved in a reaction changes from 4.0 m to 2.0 m in 40 minutes. is the substance a reactant or a product?

In the given problem above, the concentration of the substance actually decreases over a period of 40 minutes from 4.0 M to 2.0 M. This signifies that it is being used up during the reaction; thus, making it a reactant. If its concentration were to increase instead, this would make it a product. 

Answer:

5.6⋅10−^19  j

do you need the explaination?

Use a magnet to separate iron, evaporate water, i'm not sure how to separate the other two i'm sorry but good luck