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)

Question

Responses

conduct a test to determine the chemical makeup of the molecules
conduct a test to determine the chemical makeup of the molecules

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

observe a color change
observe a color change

test for the release of heat

Answer 1

A reliable way to observe that a chemical change has occurred when two substances come in contact with one another is to monitor for the release of a gas.

While observing a color change and testing for the release of heat can also indicate a chemical change, the release of gas is often a strong and clear indicator that a chemical reaction has occurred. Conducting a test to determine the chemical makeup of the molecules is not immediate and would not directly indicate a change during the initial contact of the substances.