A chemical equation is balanced when the number of each kind of element on the left side of the yield sign is equal to the number of each kind of element on the right side.Edit. Share to:Chrishan Silva.o balance a chemical equation, you can change the coefficients (number of molecules). Remember: You cannot change the subscripts. When we balance an equation we change the … number of atoms on one or both sides of the equation by means of simple mathematical calculation.