Post on 31-Mar-2015
Chemical vs. Physical
Chemical Change involves breaking and/or making Bonds
Chemical Change involves breaking and/or making Bonds
Chemical Change involves breaking and/or making Bonds
Chemical Change involves breaking and/or making Bonds
Physical Change doesn’t involve breaking and/or making Bonds
Physical Change doesn’t involve breaking and/or making Bonds
Physical Change doesn’t involve breaking and/or making Bonds
Physical Change doesn’t involve breaking and/or making Bonds
Physical Change doesn’t involve breaking and/or making Bonds
Physical Change doesn’t involve breaking and/or making Bonds
Physical Change doesn’t involve breaking and/or making Bonds
Physical Change doesn’t involve breaking and/or making Bonds
Dissolving Ionic Compounds is a little bit of a Gray area, but is considered to be a
Physical Change.
Physical Change doesn’t involve breaking and/or making Bonds
In General, Physical Changes are easily reversed,
Chemical Changes are not!
In General, Physical Changes are easily reversed,
Chemical Changes are not!
Chemical Change involves breaking and/or making Bonds
In the Lab, you can’t see the bonds being broken and/or made!
• How do you tell if a change is a Chemical Reaction or a Physical Change?
4 OBSERVATIONS that Tend to indicate that a change is Chemical:1. Color Change
4 OBSERVATIONS that Tend to indicate that a change is Chemical:1. Color Change
2. Heat and/or Light Produced
4 OBSERVATIONS that Tend to indicate that a change is Chemical:1. Color Change
2. Heat and/or Light Produced
3. Gas Produced
4 OBSERVATIONS that Tend to indicate that a change is Chemical:1. Color Change
2. Heat and/or Light Produced
3. Gas Produced
4. Precipitate Formed
4 OBSERVATIONS that Tend to indicate that a change is Chemical:1. Color Change
2. Heat and/or Light Produced
3. Gas Produced
4. Precipitate Formed
4 OBSERVATIONS that Tend to indicate that a change is Chemical:1. Color Change
2. Heat and/or Light Produced
3. Gas Produced
4. Precipitate Formed-Usually see clear solution turn cloudy before solid settles.
4 OBSERVATIONS that Tend to indicate that a change is Chemical:1. Color Change
2. Heat and/or Light Produced
3. Gas Produced
4. Precipitate Formed-Usually see clear solution turn cloudy before solid settles.
Be aware of Physical Changes that can APPEAR to be Chemical!
4 OBSERVATIONS that Tend to indicate that a change is Chemical:1. Color Change – Watch for Color Mixing
2. Heat and/or Light Produced
3. Gas Produced
4. Precipitate Formed-Usually see clear solution turn cloudy before solid settles.
Be aware of Physical Changes that can APPEAR to be Chemical!
4 OBSERVATIONS that Tend to indicate that a change is Chemical:1. Color Change – Watch for Color Mixing
2. Heat and/or Light Produced – Some Physical Changes produce heat
3. Gas Produced
4. Precipitate Formed-Usually see clear solution turn cloudy before solid settles.
Be aware of Physical Changes that can APPEAR to be Chemical!
4 OBSERVATIONS that Tend to indicate that a change is Chemical:1. Color Change – Watch for Color Mixing
2. Heat and/or Light Produced – Some Physical Changes produce heat
3. Gas Produced – Watch for release of trapped gas, or boiling
4. Precipitate Formed-Usually see clear solution turn cloudy before solid settles.
Be aware of Physical Changes that can APPEAR to be Chemical!
4 OBSERVATIONS that Tend to indicate that a change is Chemical:1. Color Change – Watch for Color Mixing
2. Heat and/or Light Produced – Some Physical Changes produce heat
3. Gas Produced – Watch for release of trapped gas, or boiling
4. Precipitate Formed- Adding a solid that doesn’t dissolve doesn’t count!
Be aware of Physical Changes that can APPEAR to be Chemical!
Chemical Properties(AKA “Will they react?”)
• Sodium reacts with water
• Gold does not react with acids
• Hydrogen reacts with oxygen
• Copper does not react with salt (NaCl)
Physical Properties:Can be measured without trying to
react the substance.• Sodium is malleable
• Gold has a density of 19 g/mL
• Hydrogen is colorless
• Copper conducts electricity
Physical Properties:Can be measured without trying to
react the substance.• Sodium is malleable
• Gold has a density of 19 g/mL
• Hydrogen is colorless
• Copper conducts electricity
Note that color is a Physical Property, but a color CHANGE is an indication of a
Chemical Reaction.