What does it mean to say that “atoms are not created or destroyed” in a chemical reaction? Explain how this relates to products and reactants in a chemical reaction. Explain how this demonstrates conservation of mass in a chemical reaction.

This means that in a chemical reaction, the atoms in the reactants are the only atoms that can end up in the products

Explanation:If you add more reactants, more products will be produced.

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 !