AP Chemistry / Unit 4: Chemical Reactions
4.4 Physical and Chemical Changes
Notes
- Physical change: changes IMFs only (melting, dissolving molecular solutes).
- Chemical change: breaks and forms bonds, making new substances.
- Dissolving ionic solids is a gray area (ionic bonds break).
Practice
Boiling water is:
$\mathrm{H_2O}$ stays $\mathrm{H_2O}$.
Burning wood is:
New substances form.
During a physical change, which are overcome?
Molecules stay intact.
Ready for more? Take the Unit 4 test.