Chemical and physical properties power point.ppt
- 1. Chemical and physical properties
- 2. Matter • All matter has 2 types of properties: Physical properties and chemical properties.
- 3. Physical properties • A physical property is a characteristic of a substance that can be observed without changing the substance into another substance. – (You can see it without changing what you’re looking at into something else.)
- 4. Physical Properties - Examples • Examples physical properties include: – Volume – Mass – Weight – Size
- 5. Physical Properties - Examples • Examples physical properties include: – Density – Melting point – Boiling point
- 6. Physical Properties - Examples • Other physical properties include: – Color – Hardness – Odor – Taste – State of matter – Texture – Luster (shine) – Flexibility – Heat conductivity – Electrical conductivity – Solubility (ability to dissolve in water.) – Shape – Viscosity – Ductility – Malleability
- 7. Chemical properties • A Chemical property is a characteristic of a substance that can only be observed by changing it into a different substance.
- 8. Chemical properties - Examples • Examples of chemical properties include: – The ability to burn – Ability to tarnish – Ability to rust – Ability to decompose – Ability to react with other chemicals – Instability – Ability to do acid/base reactions
- 9. Chemical and physical changes
- 10. Physical Change • A Physical change is a change in a substance that does not change what the substance is.
- 11. Physical Change - examples • Examples of physical change include: – Change in shape – Change in size – Change in phase • Melting (solid to liquid) • Boiling (liquid to gas) • Evaporation (liquid to gas) • Condensation (gas to liquid) • Freezing (liquid to solid) • Sublimation (solid to gas) • Deposition (gas to solid)
- 12. Physical Change • Physical changes might be caused by: – Grinding – Cutting – Crushing – Bending – Breaking – Heating/cooling • (change in phase) – squishing
- 13. Physical Change • Evidence that a physical change has occurred might include: – Change in shape – Change in form – Change in size – Change in phase (This is always a physical change!) – Physical changes are usually reversible
- 14. Chemical change • A chemical change is a change in which a substance is changed into a different substance. (You’ve changed what it is.)
- 15. Chemical change • Examples of chemical changes include: – Burning – Rusting – Tarnishing
- 16. Chemical change • Chemical changes occur when a chemical reaction causes bonds between atoms to break or to form.
- 17. Chemical Change: Evidence • Evidence that a chemical change has occurred might include: – A color change – An odor change – Formation of a precipitate (you mix two liquids and make a solid) – Gas is formed (bubbles) – Changes in physical properties.
- 18. Physical and Chemical change • During a chemical change energy can be released in the form of: – Heat – Light
- 19. Chemical change – Chemical reactions • When a chemical change occurs, energy is either released or absorbed.
- 20. Physical and Chemical change - heat • A chemical reaction that releases energy in the form of heat is called exothermic. – Heat comes OUT • Exo = out • Thermic = heat – It will feel HOT.
- 21. Physical and Chemical change - heat • A chemical reaction that absorbs energy in the form of heat is called endothermic. – Heat goes IN • Endo = in • Thermic = heat – It will feel COLD