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Physical vs. Chemical Changes

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Physical Property Physical Changes Molecules in Physical Changes Chemical Property Chemical Changes PowerPoint Presentation Signs of Change PowerPoint ... – PowerPoint PPT presentation

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Title: Physical vs. Chemical Changes


1
Physical vs. Chemical Changes
2
Warm-up
21 October 2013
From the Cooking with Chemistry activity,
describe how did you use phase change to complete
the final task of separating the salt from the
solution?
http//whatscookingamerica.net/Foto4/BoilingWater.
bmp
3
Standard
21 October 2013
5.a. I know reactant atoms and molecules interact
to form products with different chemical
properties.
4
Physical Property Chemical Property    
Example Example      
Physical Change   Chemical Change
Example   Example  
Signs of a physical change Signs of a chemical change
5
Whats the Difference?
  • Matter can change
  • Examples Freeze, cut, burn, etc.
  • 2 types of changes
  • Physical changes
  • Chemical changes

6
Physical Property
  • Characteristic of matter that does not change the
    substance (using senses)

7
Physical Changes
  • Matter changes form WITHOUT becoming something
    new
  • You start and end with same thing (see below)
  • Examples cutting, freezing, melting, etc.

8
Molecules in Physical Changes
9
Chemical Property
  • Describes matter on its ability to change into
    new matter
  • Flammability ability of substance to burn
  • Reactivity ability of substance to change into
    new substance

10
Chemical Changes
  • Matter changes, becomes NEW substance
  • Start and end with different things
  • Usually irreversible (cant change back)
  • Examples burning, rusting, milk going sour

11
(No Transcript)
12
Signs of Change
  • Physical
  • Size
  • Shape
  • Texture
  • Chemical
  • Temperature
  • Color
  • Bubbles/fizzing
  • Smoke
  • Smell

13
Chemical Change _________________ In chemical
changes, atoms and molecules re-arrange to form
new substances.
Reactants   Products
14
Molecules in Chemical Changes
  • The atoms arrange to make a new substance

15
Chemical Change Reaction
Mixing Things Up Chemical Change
Demos Observations of Reactants
______________ Liquid ____________ Powder/dry
  • Observations during the demonstration
  • Products the resulting solutions in a reaction
  • Reactants starting solutions in a reaction

  I noticed the    
16
Chemical Change Reaction
Question Answer
A chemical reaction between two materials occurs if the properties of the products (what you make) are different from the reactants (what you mix). Was what you observed today a chemical reaction? Explain!
  • Products the resulting solutions in a reaction
  • Reactants starting solutions in a reaction

17
Chemical Change Reaction
Chemical reactions have formulas just like
molecules and compounds. As a class, we will
write the chemical equation below and label the
reactants and the products.
Chemical Formula
Reactants     Products
In words
Reactants     Products
  • Products the resulting solutions in a reaction
  • Reactants starting solutions in a reaction

18
Chemical Reaction Demo
  • NaHCO3 NaOOCCH3
  • HOOCCH3 H2O CO2

Sodium Acetate, water, and carbon dioxide
Sodium Bicarbonate and Acetic Acid
19
Chemical Change Reaction
Summary
  • How can you tell if a chemical reaction happened?
  • What are evidences to support that chemical
    reaction happened?
  • After a chemical reaction will it be possible to
    bring back the reactants to their original form
    (state and properties)?
  • How is chemical reaction related to chemical
    change?
  • Products the resulting solutions in a reaction
  • Reactants starting solutions in a reaction

20
Signs of Chemical Change
Fizzing/gas formation
Flash/light
smoke
Change in temperature
Change in color
Smell/odor
21
Warm-up
21 October 2013
Give an example of a physical change and a
chemical change, and then describe how they are
different from the other. Explain your answer in
2-3 sentences.
22
Warm-up
21 October 2013
Why is cooking/baking similar to science? Explain
your answer.
23
Physical Change vs. Chemical Change
Objective To correctly identify and differentiate physical change from chemical change.
Question Are changes (physical and chemical) only present inside the laboratory? How are physical change different from chemical change?
Hypothesis If physical change does not produce a new product, then I can .
24
Chemical Change Reaction
Observations
Steps Physical or Chemical
 
 
 
 
 
 
  • Products the resulting solutions in a reaction
  • Reactants starting solutions in a reaction

25
Chemical Change Reaction
Observations
Steps Physical or Chemical
Breaking graham crackers  
 
 
 
 
 
  • Products the resulting solutions in a reaction
  • Reactants starting solutions in a reaction

26
Chemical Change Reaction
Observations
Steps Physical or Chemical
Breaking graham crackers  
Breaking chocolate bar  
 
 
 
 
  • Products the resulting solutions in a reaction
  • Reactants starting solutions in a reaction

27
Chemical Change Reaction
Observations
Steps Physical or Chemical
Breaking graham crackers  
Breaking chocolate bar  
Cooking Marshmallow  

 
 
  • Products the resulting solutions in a reaction
  • Reactants starting solutions in a reaction

28
Chemical Change Reaction
Observations
Steps Physical or Chemical
Breaking graham crackers  
Breaking chocolate bar  
Cooking Marshmallow  
Stacking cracker, chocolate, and marshmallow  
 
 
  • Products the resulting solutions in a reaction
  • Reactants starting solutions in a reaction

29
Chemical Change Reaction
Observations
Steps Physical or Chemical
Breaking graham crackers  
Breaking chocolate bar  
Cooking Marshmallow  
Stacking cracker, chocolate, and marshmallow  
Chocolate melting  
 
  • Products the resulting solutions in a reaction
  • Reactants starting solutions in a reaction

30
Chemical Change Reaction
Observations
Steps Physical or Chemical
Breaking graham crackers  
Breaking chocolate bar  
Cooking Marshmallow  
Stacking cracker, chocolate, and marshmallow  
Chocolate melting  
Eating smore!  
  • Products the resulting solutions in a reaction
  • Reactants starting solutions in a reaction

31
Chemical Change Reaction
Discussion/Summary
  • How will you know if an object underwent a
    chemical or physical change?
  • Can changes happen outside of the science
    classroom or laboratory?
  • Products the resulting solutions in a reaction
  • Reactants starting solutions in a reaction

32
Physical Change v. Chemical Change
  • Make a Venn Diagram to compare the 2 types of
    changes

33
Is it a chemical or physical change?
  • Sugar dissolving in tea
  • Chemical Change
  • Physical Change

34
OOPS!
  • Did it change size, color, shape (Physical
    Change)?
  • or
  • Did it become different matter (Chemical Change)?

35
Correct!
36
Is it a chemical or physical change?
  • Logs burning
  • Chemical Change
  • Physical Change

37
OOPS!
  • Did it change size, color, shape (Physical
    Change)?
  • or
  • Did it become different matter (Chemical Change)?

38
Correct!
39
Is it a chemical or physical change?
  • Breaking water up by separating it into hydrogen
    and oxygen
  • Chemical Change
  • Physical Change

40
OOPS!
  • Did it change size, color, shape (Physical
    Change)?
  • or
  • Did it become different matter (Chemical Change)?

41
Correct!
42
Is it a chemical or physical change?
  • Cutting paper
  • Chemical Change
  • Physical Change

43
OOPS!
  • Did it change size, color, shape (Physical
    Change)?
  • or
  • Did it become different matter (Chemical Change)?

44
Correct!
45
Is it a chemical or physical change?
  • Crushing an aspirin
  • Chemical Change
  • Physical Change

46
OOPS!
  • Did it change size, color, shape (Physical
    Change)?
  • or
  • Did it become different matter (Chemical Change)?

47
Correct!
48
Is it a chemical or physical change?
  • Metal rusting
  • Chemical Change
  • Physical Change

49
OOPS!
  • Did it change size, color, shape (Physical
    Change)?
  • or
  • Did it become different matter (Chemical Change)?

50
Correct!
51
Is it a chemical or physical change?
  • An egg rotting
  • Chemical Change
  • Physical Change

52
OOPS!
  • Did it change size, color, shape (Physical
    Change)?
  • or
  • Did it become different matter (Chemical Change)?

53
Correct!
54
Is it a chemical or physical change?
  • An egg breaking
  • Chemical Change
  • Physical Change

55
OOPS!
  • Did it change size, color, shape (Physical
    Change)?
  • or
  • Did it become different matter (Chemical Change)?

56
Correct!
57
Endothermic and Exothermic Reactions
  • Standards 8.5.c.
  • I know chemical reactions usually liberate or
    absorbs heat.

58
When chemical reactions occur, the connections
between atoms must be broken and rearranged. In
order to do this, ________________ is involved in
all chemical reactions.
Heat
59
There are 2 Types of Reactions Involving Heat


Endothermic
Exothermic
  • Outside-Heating
  • Exo Exit
  • Therm/ic Heat
  • Within-Heating
  • Endo Enter
  • Therm/ic Heat

60
There are 2 Types of Reactions Involving Heat
(cont.)
Endothermic Exothermic
  • Reactions in which the system releases heat to
    the surrounding.
  • Reactions in which the system absorbs heat from
    the surrounding.

61
There are 2 Types of Reactions Involving Heat
(cont.)
Endothermic Exothermic
It feels It feels
Cold
Hot
62
There are 2 Types of Reactions Involving Heat
(cont.)
Endothermic Exothermic
Examples Examples
  • Candle flame
  • Rusting Iron
  • Cooking an egg
  • Baking a bread

63
Frayer Model
Exothermic Reaction
64
Frayer Model
Endothermic Reaction
65
Chemical Change Reaction
Weekly Reflection/Exit Slip
  • Name 4 items you learned in this weeks lesson.
  • If Mr. Rivera will teach the lesson again, will
    you want it done differently?
  • If you want it done differently, why and how
    would you want it?
  • If you want it done the same, why?
  • Products the resulting solutions in a reaction
  • Reactants starting solutions in a reaction
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