Answer:
Na2O + 2HCl -> 2NaCl + H2O then it wil be 10.3 atoms left in the cycle
Step-by-step explanation: you would take
(Na2O) then (HCl) then (NaCl) and, (H2O)
And you would got to the table of atoms and put them together if you look at the name of a chemical it show a number well you would divide them in to fractions and the denominator you would need to focus on because that is going to be your answer.