A scientist drips a colorless liquid into a container that has a reddish orange liquid in it. The scientist swirls the container. After a while, the liquid in the container turns green, and then purple.

Question

What is the indicator that a chemical change has occurred in this example?

Responses

The liquid in the container changes color.
The liquid in the container changes color.

The scientist adds the liquid slowly, drop by drop.
The scientist adds the liquid slowly, drop by drop.

The scientist swirls the container.
The scientist swirls the container.

The liquid dripped into the container is colorless.
The liquid dripped into the container is colorless.

Answer 1

The key indicator that a chemical change has occurred in this example is:

The liquid in the container changes color.

The change in color from reddish orange to green, and then to purple, suggests that a chemical reaction has taken place, resulting in new substances being formed.