16. Which of the following is an example of a chemical change? A Ascientist heats a copper penny until it melts and turns liquid
B Your mother mixes sugar and water, creating lemonade for you to drink.
C Water spilled on the ground disappears over time
D A cold pack is snapped, causing the temperature to suddenly drop.

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. 1-condensation of ethanol 2-evaporation of ethanol 3- formation of carbon dioxide gas from glucose burning of natural gas 4-formation of ethanol from glucose by yeast 5-formation of a carbon deposit inside the flask

All cells are made of four types of acids, lipids, proteins, and carbohydrates.

Calculate the ph of a .10m nh4cl solution. the kb value for nh3 is 1.8×10^-5