. Consider the following reaction : 4NH3+502 → 4NO + 6H20,suppose we start the reaction with 100 molecule of NH3 and 100 molecule of
O2, what will be the total number of molecule (reactant and product)
after this reaction goes to completion?

Which of the following is an indication that a substance has undergone a chemical change? a. no new product has been formed. b. the color of the substance has not changed. c. the original constitute has not changed. d. the molecular structure has changed.