Physical and chemical changes | Chemical reactions | AP Chemistry | Khan Academy | Summary and Q&A

22.6K views
December 3, 2020
by
Khan Academy
YouTube video player
Physical and chemical changes | Chemical reactions | AP Chemistry | Khan Academy

TL;DR

This video explains the difference between physical and chemical changes and provides examples of each.

Install to Summarize YouTube Videos and Get Transcripts

Key Insights

  • 💱 Physical changes involve a change in properties without a change in composition.
  • 💱 Chemical changes involve a change in composition with bonds breaking and forming.
  • 💱 Overcoming intermolecular forces generally indicates a physical change, while forming or breaking chemical bonds indicates a chemical change.
  • 🍳 The combustion of propane is a chemical change as bonds in the molecules break and reform.
  • 👶 Rusting of iron involves a chemical change as new ionic bonds are formed.
  • 💦 Dissolving sodium chloride in water is a gray area, as it can be considered both a physical and chemical change.
  • 💱 Evaporating saltwater can be seen as both a physical change (water evaporating) and a chemical change (reforming ionic bonds).

Transcript

Read and summarize the transcript of this video on Glasp Reader (beta).

Questions & Answers

Q: What is the difference between a physical change and a chemical change?

In a physical change, properties may change, but the composition remains the same. In a chemical change, the composition changes as bonds break and form.

Q: Is ice melting into water a physical or chemical change?

Ice melting into water is a physical change because the composition of the water molecules remains the same.

Q: What happens during the combustion of propane?

The combustion of propane involves a chemical change. The bonds in propane and oxygen molecules break and reform, resulting in the production of carbon dioxide and water.

Q: Is dissolving sodium chloride in water a physical or chemical change?

Dissolving sodium chloride in water is a gray area, as it can be considered both a physical and chemical change. The ionic bonds between the sodium and chloride ions are broken, but the constituent ions are still present.

Summary & Key Takeaways

  • Physical changes involve a change in properties without a change in composition, such as ice melting into water.

  • Chemical changes involve a change in composition, with bonds breaking and forming, like propane combusting into carbon dioxide and water.

  • Dissolving sodium chloride in water is a gray area, as it can be considered both a physical and chemical change.

Share This Summary 📚

Summarize YouTube Videos and Get Video Transcripts with 1-Click

Download browser extensions on:

Explore More Summaries from Khan Academy 📚

Summarize YouTube Videos and Get Video Transcripts with 1-Click

Download browser extensions on: