Which of the following is a reliable way to observe that a chemical change has occurred when two substances come in contact with one another?(1 point)

Responses

observe a color change
observe a color change

monitor for the release of a gas
monitor for the release of a gas

test for the release of heat
test for the release of heat

conduct a test to determine the chemical makeup of the molecules

All of the above options are reliable ways to observe that a chemical change has occurred when two substances come in contact with one another.

All of the responses provided can be reliable ways to observe that a chemical change has occurred. However, since the first two options are the same, it seems there may be a duplication. Thus, the correct response would be:

1. Observe a color change.
2. Monitor for the release of a gas.
3. Test for the release of heat.
4. Conduct a test to determine the chemical makeup of the molecules.