What is the MAIN difference between the independent and dependent variable?

independent variable is how it changes how it affects something else dependent variable is something being measured

An independent variable is the variable which is changed by the scientist also called the manipulated variable. The dependent variable is the result of the action of the independent variable. it is the factor that changes due to the independent variable. It is also known as the responding variable.

Explanation

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 !