Physical Science 17

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Chemical Reactions

Chemical reactions are a process. These reactions involve rearrangement of the molecular or ionic structure of a substance. Chemical reactions are in contrast to a change in physical form (such as liquid water into ice), or a nuclear reaction.


Day 1 – Introduction
Day 2 – Virtual Textbook


0:57 Five Chemical Reactions

5:34 Types of Chemical Reactions

1:36 Five Major Chemical Reactions



One of the five types of chemical reactions is called “synthesis” – but sometimes it is instead called “combination.” Both of these words mean essentially the same thing. But some textbooks and videos use “synthesis” – while others use the word “combination.” Some students and instructors wish all the information sources would just settle on one of the words, believing it is too confusing to have two words used for the same concept. Other students and instructors are just fine with using both words – they can be interchanged with each other.

  • Position A: Everyone should use just one of the words – either are okay – but to avoid confusion, either “synthesis” or “combination” should be used at all times.
  • Position B: It is no big deal to use two different words for conveying one concept. Using both of the words (interchanging them at times) is perfectly okay.

Instructor Resources

Standard Daily Material
  • Day 1 – Standard material – introduction day
  • Day 2 – Standard material – reading day
  • Day 3 – Standard material – make a presentation
  • Day 4 – Standard material – give a presentation
  • Extra! – Enrichment and remediation options
Other Topic Specific Resources

Special Notes and Notices

Instructor Emphasis:

  • Science & Engineering Practice: Plan and conduct investigations.
  • Cross-Cutting Concept: Cause and Effect: Mechanisms and explanations.
Standards Concepts
  • All matter is conserved, just broken apart and rearranged to form new molecules/substances.
  • A chemical bond is an attractive force not a physical thing at all.
  • Although the substance changes forms, the atoms are still there. In a closed system you will see no change in mass.
  • A chemical reaction will only happen if a collision occurs, however more requirements, such as orientation and available kinetic energy, must also be met.
  • All matter is conserved, just broken apart and rearranged to form new molecules/substances.