Physical vs Chemical Changes
- A physical change is a change in the form of a substance, not in its chemical composition = reversible
- A physical change can be used to separate a mixture into pure compounds, but will not break compounds into elements
- Ex: phase changes, separation techniques (Distillation, filtration, chromatography), dissolving
- Involve changes in intermolecular forces
- Physical properties: shape, solubility, density, volume, & interparticle distance at diff temperatures (& phases) may change but composition stays the same
- A physical change can be used to separate a mixture into pure compounds, but will not break compounds into elements
- Chemical change: a substance becomes a new substance with different properties and composition
- Ex: rusting, bunsen burner (burning), acid, combustion (reacted with oxygen)
- In chemical changes, one substance changes to another by reorganizing the way the atoms are attached to each other → involve changes in intramolecular forces
- Bonds have been broken, and new ones have been formed
- Indicators of chem change: temp, light, or color change, gas or precipitate formation
Example: Dissolving NaCl
- Can be argued both ways bcuz is reversible (physical change) and ionic bonds are broken (chemical)