Which of the following is responsible for producing light, heat, chemical, and magnetic changes?

• A. Chemical reactions
• B. Mixtures
• C. Phase transitions
• D. Physical changes

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the types of changes listed: chemical reactions, mixtures, phase transitions, and physical changes.
2. Step 2: Recognize that chemical reactions involve the making and breaking of chemical bonds, which can produce light, heat, chemical, and magnetic changes.
3. Step 3: Note that mixtures are combinations of substances without chemical bonding, so they do not inherently produce these changes.
4. Step 4: Understand that phase transitions (like melting or boiling) involve changes in physical state and typically involve heat but not chemical or magnetic changes.
5. Step 5: Realize that physical changes affect only physical properties without altering chemical composition, so they do not produce chemical or magnetic changes.