what is the reactant(s) in the chemical equation below?
cu(s) + 2agno3(aq) → 2ag(s) + cu(no3)2(aq)

a. 2ag(s) + cu(no3)2(aq)
b. 2ag(s)
c. cu(s) + 2agno3(aq)
d. cu(s)

C ) Cu(s) + 2AgNO3(aq)

Explanation:

A chemical reaction is represented by a chemical equation which show the reactant and products. Reactants are written on left side of arrow while products are written on right side. The number of atoms are remain same however arrangement of atoms is different on both side.

For example:

Cu(s) + 2AgNO3(aq) →   2Ag + Cu(NO3)2

In this reaction Cu and AgNO3 are reactants while Ag and Cu(NO3)2 are products.The number of atoms are same on both side however arrangement of atoms is different.

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 !