A Mark for Review When a 50. mL sample of C2H;OH is mixed with a 50. mL sample of H2O, the resulting mixture has a volume of 95 mL, and the container is warm to the touch. Which of the following best describes these observations? (a) A chemical reaction occurs, as evidenced by the volume of the resultant mixture being less than the total volume of the initial components. A chemical change occurs, as evidenced by the formation of new covalent bonds releasing more energy than is absorbed by the breaking of the existing covalent bonds. A physical change occurs, and the solvation process is exothermic. A physical change occurs, and the solvation process is endothermic