Question

Part D

After about 30 minutes, observe the substances in the test tubes again. Record your observations. Include any evidence


of a chemical reaction.


A Caution! If you plan to leave your substances unattended, be sure they are in a safe location away from young children


and pets.

Answer 1

When observing substances in test tubes, record observations and look for evidence of a chemical reaction, such as temperature changes, light emission, color changes, and the formation of bubbles.

Step-by-step explanation:

When observing the substances in the test tubes after about 30 minutes, you should record your observations and look for any evidence of a chemical reaction. Some observations that can indicate a chemical reaction include:

• Temperature changes: The temperature may increase or decrease.
• Light given off: There may be the emission of light.
• Color changes: The substances in the test tubes may change color, forming a different colored substance.
• Bubbles formed: Bubbles may be produced, indicating the release of a gas.

These observations help determine whether a chemical reaction has occurred.