Question

In a laboratory experiment, a fermenting aqueous solution of glucose and yeast produces carbon dioxide gas and ethanol. The solution was heated by burning natural gas in a Bunsen burner to distill the ethanol that formed in the flask. During the distillation, the ethanol evaporated and then condensed in the receiving flask. The flame of the burner was kept too close to the bottom of the flask and some of the glucose decomposed into a black carbon deposit on the inside of the flask. During this experiment the following changes occurred. Which of these changes involved a physical change and not a chemical change? Check all that apply. Check all that apply.1-condensation of ethanol2-evaporation of ethanol3- formation of carbon dioxide gas from glucose burning of natural gas4-formation of ethanol from glucose by yeast5-formation of a carbon deposit inside the flask

Answer 1

Answer: 1) condensation of ethanol and 2)evaporation of ethanol are physical changes

Explanation: All physical changes correspond to changes in the state of the same compound: liquid, vapor, solid. However, any type of formation indicates a chemical change because a new compound is formed or a byproduct is formed.