How many moles of water can be produced with 4.3 moles of H2 and 5.6 moles of O2? Which reactant is limiting ? How many moles of the excess will be left after the reaction?

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.