How are natural elements different from other elements ?

Synthetic elements are man-made elements. ... Synthetic elements are unstable chemical elements and they are not naturally found on the earth. These elements are synthesized in the laboratory. All of them are unstable and radioactive in nature, which means they emit radiations and decay into other elements.

your answer would be a. 12.5 kg

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 !