An experiment is performed in which a crystalline substance is added to a beaker filled with room temperature water. the following observations are made: i. the crystals dissolve ii. a precipitate is formed. iii. the bottom of the beaker feels warm to the touch. iv. bubbles begin forming within the water. all of the observations are evidence of a chemical change except - a. observation i b. observation ii. c. observation iii. d. observation iv.