physical and chemical changes - school district #308 ... · matter can be described and identified...
TRANSCRIPT
Physical and Chemical Properties
Book K
Warm Up: As you view the video clip, list examples of physical and chemical changes .
Physical Change Chemical Change
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Warm Up: As you view the video clip, list examples of physical and chemical changes .
Physical Change Chemical Change
1.
2.
3.
4.
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2.
3.
4.
Why are these physical changes? Why are these chemical changes?
Matter
Anything that has mass and takes up space!
Matter can be described and identified by physical and chemical properties. Physical properties have to do with appearance. You can observe many physical properties with your senses and by measuring the length, width, height, mass and density of a substance.
Physical properties include color, shape, smell, texture, taste, and size.
The state of matter (whether it’s a solid, liquid or a gas) and the temperature at which the substance boils, melts, or freezes are also physical properties.
We can group objects by their properties. How can we group these objects?
1. Did you sort them by color?
One property is color.
Color
Red
Green
Yellow
Size
Large objects
Small objects
2. Did you sort them by size?
A second property is size.
Circles
Squares Triangles
3. Did you sort them by shape?
A third property is shape.
Shape
Chemical properties on the other hand, have more to do with the atomic or molecular composition of matter.
Chemical properties deal with how substances react with other substances such as air, water, or fire.
A chemical change has occurred when a substance has changed into something new or different so that the original substance is gone.
Concept of Change
Change: altering or transforming from one form to another
How can you change your hair?
Concept of Change
Change: altering or transforming from one form to another
Physical Change a change that occurs that does not alter the identity of the substance
Chemical Changes one or more substances are changed into new substances with new and different properties
Homework:
Read interactive text p. 1-5 #1-16 Answer questions in the margins
Answers to p. 1-5 # 1-16 1. volume: liter
mass: kilogram
weight: Newton
2. Amount of space an object takes up
3. 1900 mL
4. Curved surface of a liquid in a container
5.
6. Volume
7. Area
8. 1 m2
Answers to p. 1-5 # 1-16 9. Put known volume of water in a g.c. add car and
measure increase in water level
10. Amount of matter in an object
11. Weight
12. No, Yes
13. Kg, g, mg
14. Newton (N)
15. Resisting a change in motion
16. Higher mass, more inertia
What are some physical properties of this ice cube?
What are some chemical properties of fireworks?
Concept of Change
Change: altering or transforming from one form to another
Physical Change a change that occurs that does not alter the identity of the substance
Examples: Physical Change
Sand a piece of wood
Sawdust is still wood!
Examples: Physical Change
Melting Butter
Examples: Physical Change
Dissolve Drink Mix
If you heat the mixture the water evaporates and solid sugar is left
Examples: Physical Change
Melting Ice
Physical Change
Why is this a physical change?
Chemical Changes one or more substances are changed into new substances with new and different properties
A chemical change is called a chemical reaction
Examples: Chemical Change
Digestion of food
Rotting Cooking
Rusting Burning
Chemical Change
Why is this a chemical change?
Evidence of a physical change:
1. Substance not changed- just size/shape
Still Paper!
Evidence of a physical change:
2. Changing state of matter
Solid Liquid
Evidence of a physical change:
3. Dissolving
Evidence of a physical change:
4. Bending, crushing, mixing
Evidence of a physical change:
5. Might be reversible
Evidence of a chemical change:
1. Color change
Evidence of a chemical change:
2. Gas produced: fizzing, foaming, bubbles
Evidence of a chemical change:
3. Heat
Evidence of a chemical change:
4. Sound or light produced
Evidence of a chemical change:
5. New substance is formed
Burning a candle produces ash, carbon dioxide and water vapor
Is it Physical or Chemical?
Change Physical Chemical
Melting cheese
Burning wood
Milk souring
Wadding up paper
Bicycle rusting
Homework:
Read interactive text p. 7-11
Answer questions in the margins
Answers to p. 7-11 # 1-15 1. Can be observed/measured without making a
new substance
2. Mass or weight, density, compressibility
3. Amount of matter in a given volume
4. Skip
5. Skip
6. When it is measured at the same temperature
and pressure
7. Zinc
8. If it is denser than water
9. Diet soda- less dense than water
Answers to p. 7-11 # 1-15 10. Liquid with the lowest density- corn oil
11. Affects the physical properties
12. Melting
13. Change of state
14. Change into a liquid or a solid
15. Nothing
When you are done checking your answers, put your
packet in the IT SECTION of your binder and take
out your notes sheet. Turn to side 2 of your notes
and find the THINK ABOUT IT data table.
Exothermic Endothermic
Gives off heat- temperature increases Absorbs heat- temperature goes down
heat energy EXITS the system
surroundings usually feel warmer
Ex: Monster Foam
Epson salts & water
heat energy ENTERS the system
surroundings usually feel cooler
Ex. Cold packs, melting ice
When you “pop” the inner pouch, the
chemical reaction absorbs heat energy
from the surroundings.