PLEASE HELP!! go back to the simulation and increase the number of molecules of heavy species to 700? What change do you observe?
contentstore. ple. platoweb. com/content/sharedmedia/phet_batch2 /gas-properties/gas-properties_en. html

Here's link to the

cutt.ly/tz3yDpb

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

i'm assuming that it's c.) red bank..