If a chemical change requires energy, which of the following could be the source of the energy?

a. heating with a flame

b. settling the mixture for 20 minutes

c. measuring mass from a balance beam

d. adding more substance to the observed material

The answer for the question given is A. Heating with a flame.

One of the processes that cause a chemical change is heating. An example of this is cooking or baking, which causes a permanent chemical change in substances. Also, all of the other choices are examples of physical changes.