When a substance is soluble in water, the smallest pieces of the substance spread out in the water as individual atoms or molecules.

How does being dissolved in water affect two substances that are chemically reacting with one another?
A.
It helps the chemical reaction occur more easily.
B.
It makes the chemical reaction occur slower.
C.
It causes the substances to react with the water.

2fe + 3h2so4 -> fe2(so4)3 + 3h2

it is necessary to balance equations in order to get the proper amount of reactants as well as products in order not to make a miscalculation.

you cannot change the subscripts as that would change the substance itself. for instance, diatomic elements such as h2 only have the subscript two when a gas. another example would be so4, if you were to change the subscript, the element would no longer be sulfate.

we change the coefficients instead as that only changes the number of molecules rather than the substance itself.

hope this !