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?
A chemical reaction (also known as a chemical change) produces substances that are chemically different from the starting materials. An example of a chemical reaction is the formation of water from hydrogen and oxygen gas. In a physical change, a substance changes its physical appearance but not its chemical identity. An example of physical change is the formation of liquid water from solid water, a familiar process called melting. Physically, liquid water looks very different from solid water (ice) but the chemical identity, water, is the same for both
Frequently Asked Questions
What scientific concept do you need to know in order to solve this problem?
Our tutors have indicated that to solve this problem you will need to apply the Physical & Chemical Changes concept. You can view video lessons to learn Physical & Chemical Changes. Or if you need more Physical & Chemical Changes practice, you can also practice Physical & Chemical Changes practice problems.