Title: Physical vs. Chemical Changes
1Physical 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.
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3 Standard
21 October 2013
5.a. I know reactant atoms and molecules interact
to form products with different chemical
properties.
4Physical Property Chemical Property
Example Example
Physical Change Chemical Change
Example Example
Signs of a physical change Signs of a chemical change
5Whats the Difference?
- Matter can change
- Examples Freeze, cut, burn, etc.
- 2 types of changes
- Physical changes
- Chemical changes
6Physical Property
- Characteristic of matter that does not change the
substance (using senses)
7Physical Changes
- Matter changes form WITHOUT becoming something
new - You start and end with same thing (see below)
- Examples cutting, freezing, melting, etc.
8Molecules in Physical Changes
9Chemical 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
10Chemical 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)
12Signs of Change
- Physical
- Size
- Shape
- Texture
- Chemical
- Temperature
- Color
- Bubbles/fizzing
- Smoke
- Smell
13Chemical Change _________________ In chemical
changes, atoms and molecules re-arrange to form
new substances.
Reactants Products
14Molecules in Chemical Changes
- The atoms arrange to make a new substance
15Chemical 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
16Chemical 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
17Chemical 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
18Chemical Reaction Demo
- NaHCO3 NaOOCCH3
- HOOCCH3 H2O CO2
Sodium Acetate, water, and carbon dioxide
Sodium Bicarbonate and Acetic Acid
19Chemical 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
20Signs 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.
23Physical 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 .
24Chemical Change Reaction
Observations
Steps Physical or Chemical
- Products the resulting solutions in a reaction
- Reactants starting solutions in a reaction
25Chemical Change Reaction
Observations
Steps Physical or Chemical
Breaking graham crackers
- Products the resulting solutions in a reaction
- Reactants starting solutions in a reaction
26Chemical 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
27Chemical 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
28Chemical 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
29Chemical 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
30Chemical 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
31Chemical 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
32Physical Change v. Chemical Change
- Make a Venn Diagram to compare the 2 types of
changes
33Is it a chemical or physical change?
34OOPS!
- Did it change size, color, shape (Physical
Change)? - or
- Did it become different matter (Chemical Change)?
35Correct!
36Is it a chemical or physical change?
37OOPS!
- Did it change size, color, shape (Physical
Change)? - or
- Did it become different matter (Chemical Change)?
38Correct!
39Is it a chemical or physical change?
- Breaking water up by separating it into hydrogen
and oxygen
40OOPS!
- Did it change size, color, shape (Physical
Change)? - or
- Did it become different matter (Chemical Change)?
41Correct!
42Is it a chemical or physical change?
43OOPS!
- Did it change size, color, shape (Physical
Change)? - or
- Did it become different matter (Chemical Change)?
44Correct!
45Is it a chemical or physical change?
46OOPS!
- Did it change size, color, shape (Physical
Change)? - or
- Did it become different matter (Chemical Change)?
47Correct!
48Is it a chemical or physical change?
49OOPS!
- Did it change size, color, shape (Physical
Change)? - or
- Did it become different matter (Chemical Change)?
50Correct!
51Is it a chemical or physical change?
52OOPS!
- Did it change size, color, shape (Physical
Change)? - or
- Did it become different matter (Chemical Change)?
53Correct!
54Is it a chemical or physical change?
55OOPS!
- Did it change size, color, shape (Physical
Change)? - or
- Did it become different matter (Chemical Change)?
56Correct!
57Endothermic and Exothermic Reactions
- Standards 8.5.c.
- I know chemical reactions usually liberate or
absorbs heat.
58When chemical reactions occur, the connections
between atoms must be broken and rearranged. In
order to do this, ________________ is involved in
all chemical reactions.
Heat
59There are 2 Types of Reactions Involving Heat
Endothermic
Exothermic
- Outside-Heating
- Exo Exit
- Therm/ic Heat
- Within-Heating
- Endo Enter
- Therm/ic Heat
60There 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.
61There are 2 Types of Reactions Involving Heat
(cont.)
Endothermic Exothermic
It feels It feels
Cold
Hot
62There are 2 Types of Reactions Involving Heat
(cont.)
Endothermic Exothermic
Examples Examples
- Candle flame
- Rusting Iron
- Cooking an egg
- Baking a bread
63Frayer Model
Exothermic Reaction
64Frayer Model
Endothermic Reaction
65Chemical 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