The activity of a radioactive substance depends on ?

The activity of a radioactive substance is measured in terms of the number of disintegrations a given radioactive sample undergoes in one second. ... More the active atoms present in the ample, more is the number of disintegrations that happen per second. It depends on the decay constant of the radioactive substance.

Explanation:

citation- https://www.quora.com/What-does-the-activity-of-a-radioactive-substance-depend-on

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 !