Physical and Chemical Changes_Introduction.ppt
- 2. Kinetic Theory of Matter THEORY OF KINETIC ENERGY A. ATOMS ARE ALWAYS MOVING B. THE MORE ENERGY ADDED TO THE ATOMS, THE FASTER & FARTHER APART THEY MOVE
- 3. Physical Changes Matter is always changing form, size, shape, color, etc. There are 2 types of changes that matter undergoes. PHYSICAL OR CHEMICAL CHANGE I. Physical Changes: a change of matter without changing the identity of the substance. IN OTHER WORDS – A CHANGE IN STATE – A CHANGE IN SIZE, SHAPE, MASS – DOES NOT CHANGE THE CHEMICAL MAKE UP OF THE MATTER – YOU HAVE WHAT YOU STARTED WITH JUST IN A DIFFERENT FORM
- 4. Examples of Physical Changes - Verbs used to describe physical changes – grind, dissolve, erode, rip, tear, break, phase change (melt, freeze, condense, etc)
- 5. Other Physical Change Examples • PAPER TORN INTO PIECES –SUGAR DISSOLVED INTO TEA –SALT DISSOLVED INTO WATER –NAILS OR HAIR CUT
- 6. Phase Changes are PHYSICAL PHYSICAL!!!!! • Types of Phase Changes: • 1. Melting • 2. Freezing • 3. Evaporization • 4. Condensation • 5. Sublimation • 6. Deposition • ALL phase changes are caused by ADDING or TAKING away energy!!!
- 7. • MATTER CHANGES FROM ONE STATE OF MATTER TO ANOTHER –WHEN HEAT (ENERGY) IS ADDED –WHEN HEAT (ENERGY IS TAKEN AWAY
- 8. DRAW THIS DIAGRAM IN YOUR NOTES!!!!
- 9. • CHANGING STATES DOES NOT CHANGE THE CHEMICAL MAKE UP OF THE MATTER • YOU HAVE WHAT YOU STARTED WITH JUST IN A DIFFERENT FORM • ICE WATER WATER VAPOR • H2O H2O H2O
- 10. • WHEN MOLECULES MOVE FASTER, THEY PRODUCE MORE FRICTION AND THEREFORE MORE HEAT. THEY SPREAD FARTHER APART & EXPAND • WHEN MOLECULES MOVE SLOWER, THEY CAUSE LESS FRICTION AND THEREFORE LESS HEAT & CLOSER TOGETHER & CONTRACT
- 11. Melting 1. MELTING – matter changing FROM A SOLID TO A LIQUID. – Energy is added – When more heat (energy) is added to matter the particles move faster till the bonds break. – Decrease density except ice to water.
- 12. Evaporation/Vaporization 2. EVAPORATION – Matter changing FROM A LIQUID TO A GAS AT THE SURFACE – ENERGY IS ADDED TO SURFACE OF LIQUID – THE PARTICLES AT THE SURFACE MOVE FASTER breaking bonds. – Decreases density. • VAPORIZATION- a general term for any substance changing to a gas.
- 13. Boiling 3. BOILING – matter changing FROM A LIQUID TO A GAS ALL THROUGHOUT THE LIQUID – ENERGY IS ADDED TO ALL OF LIQUID – PARTICLES MOVE FASTER ALL THROUGH THE LIQUID – SOME PARTICLES MOVE FAST ENOUGH TO CHANGE TO GAS WHILE THEY ARE IN THE MIDDLE OF THE LIQUID – DENSITY DESCREASES – Water boils at 212 F, 100C. • EX: pan of liquid on the stove • VAPORIZATION- a general term for any substance changing to a gas.
- 14. VAPORIZATION!!! • Remember that vaporization is a general word for any substance changing to a gas. • Boiling, evaporation, and sublimation are ALL examples of vaporization!!!
- 15. Condensation 4. CONDENSATION – Matter CHANGING FROM A GAS TO A LIQUID – ENERGY IS REMOVED • THE PARTICLES MOVE SLOWER • THE ATTRACTION BETWEEN THE PARTICLES BEGAN TO PULL THE PARTICLES CLOSER TOGETHER & THE MATTER TURNS INTO A LIQUID • DENSTITY INCREASES • Ex: dew in the lawn, water running down mirror, ring on table under glass.
- 16. Freezing • FREEZING – CHANGING FROM A LIQUID TO A SOLID – ENERGY IS REMOVED • THE PARTICLES MOVE EVEN SLOWER • THE ATTRACTION BETWEEN THE PARTICLES BEGAN TO PULL THE PARTICLES CLOSER TOGETHER & THE MATTER TURNS INTO A SOLID • Increase density. • Water freezes at 32 F, 0 C • EX: water to ice, wax or chocolate hardening
- 17. SOLIDIFICATION!!!! • Solidification is a general word for any substance changing to a solid. • Freezing and deposition are examples of SOLIDIFICATION!
- 18. Sublimation • 5. Sublimation: matter changes straight from a solid to a gas!!!! • Heat added rapidly • Molecules speed up and spread out rapidly • decrease density • Examples of Sublimation: dry ice, shrinking ice in a freezer, air freshener.
- 19. Deposition -Deposition- when matter changes from a gas directly to a solid. -Heat is taken away rapidly -Density increases -Molecules slow down and get closer together. Examples: Snowflakes, frost on a wind shield
- 21. • WHAT HAS TO HAPPEN FOR THESE CHANGES OF STATES TO OCCUR?
- 22. Bellringer 2: 1. All phase changes are: a. physical properties b. physical changes c. Chemical properties d. chemical changes 2. Condensation is: a. Liquid to gas b. Gas to solid c. Solid to gas d. gas to liquid
- 23. Let’s Sing!!!! • Phase changes are physical, physical… • Melting is physical…. Freezing is physical. • BOYS: Let me see some condensation. • GIRLS: (in high pitch voice) It’s physical. • BOYS: Let me see some sublimation. • GIRLS: (in high pitch voice) It’s physical. • Phase changes are physical, physical… • Boiling is physical… Boiling is physical… • BOYS: Let me see some deposition. • GIRLS: (in high pitch voice) It’s physical • BOYS: Let me see some evaporation. • GIRLS: (in high pitch voice) It’s physical
- 24. Chemical Changes The other way that matter can be changed is call a CHEMICAL CHANGE. II. CHEMICAL CHANGE – occurs when 2 or more substances are combined into entirely new substance with all new properties. CANNOT CHANGE IT BACK!!!!!
- 25. Chemical Change Verbs • Chemical Change Verbs: rusting, rotting, curdling, burning, cooking, light sensitivity, digesting, tarnishing.
- 26. Chemical Changes – SOME SIGNS OF A CHEMICAL CHANGE • FIZZES OR BUBBLES • COLOR CHANGE • HEAT GIVEN OFF • LIGHT GIVEN OFF • ODOR • HEAT REQUIRED FOR REACTION • NEW SUBSTANCE FORMED – Precipitate (solid) – Precipitate (gas bubbles)
- 27. • CHEMICAL CHANGE EXAMPLES –BAKING BREAD – NO LONGER HAVE FLOUR, EGGS, MILK, YEAST –ALKASELTER –BAKING SODA & VINEGAR –RUST –TARNISH