For example, the brown crust on atoaste d marshmallow is the result of sugar changing to iffer-ent substances in a mixture called caramel. A change in matterthat produces one or more new substances is a chemicalchange, or chemical reaction. The burning of gasoline in acarâs engine is a chemical change.
How much brain power does the average person use? About only 10% Though an alluring idea, the 10 percent myth is so wrong it is almost laughable, says neurologist Barry Gordon at Johns Hopkins School of Medicine in Baltimorâ¦e.
Making the world better, one answer at a time. The average weight of a human brain is 1336 grams or 2.95 pounds  for a male and 1198 grams or 2.64 pounds for a female. As a human  ages the weight of their brain tends to â¦decrease. 1 person found this useful.