Which pure substance can be classified as an element? h2 no3 nacl h2so4

The answer is :

H2

because a compound is made up of 2 or more elements.

Explanation:

An element is a substance that is made uniquely from one type of atom. For example, the element hydrogen is produced from atoms comprising a single proton and a single electron. If you change the number of protons an atom has, you develop the type of element it is.

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 !

i don,t know so just answer mine