Physical

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Physical Changes
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Did you know?

• Matter is changing around you all the time. Some
  changes are physical and some are chemical

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Do you remember what Physical Properties are???

• Color
• Shape
• Mass
• Volume

• State of Matter
• Length
• Magnetism
• Texture
• Density

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After a PHYSICAL CHANGE, the
appearance of the substance may be different but
it is still the same substance

• A physical change does not produce a new
  substance molecules are the same

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What does this mean?

• Only one substance goes into the reaction and one
  substance comes out.
• Water ? Water

Physical property States of Matter
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Cutting a Steak
?
Steak
Steak
?
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What physical property changed?

• State of matter
• Size, shape, mass, volume
• Is it still the same substance?
• This is a physical change because before and
  after being cut the substance is still steak even
  if the size, shape, and other physical properties
  changed. It changed from one bigger piece into
  smaller pieces but no new substance was produced.
  

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Bending Metal Wires
?
Metal wires
Metal wires
?
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What physical property changed?

• What physical property changed?
• Shape
• Why is this a physical change?
• Bending metal wires is a physical change because
  a physical change means that no new substance is
  produced. Although the wires look different they
  are still the same substance, metal. It just
  changed shape from flat to bent.

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Ice Cream Melting
?
Ice cream
Ice cream
?
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What physical property changed?

• State of matter
• Solid ? Liquid
• Is it still the same substance?
• This is a physical change because in a physical
  change the substance stays the same even if it
  looks different. The only thing that changed
  about the ice cream is its state of matter (solid
  to a liquid) but it is still ice cream after it
  melts.

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Exit Ticket

• A pencil being sharpened
• Evidence What physical property changed?
• Reasoning Why is this a physical change?
• 2) Water condensing on your winshield
• Evidence What physical property changed?
• Reasoning Why is this a physical change?

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Breaking glass
Glass ? Glass

• What physical property changed?
• Shape, volume, texture, mass, etc.
• Is it still the same substance?
• Yes! Still glass
• Why? It just changed from one piece to a bunch of
  smaller pieces

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Chemical Properties and Changes
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Chemical Properties
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Chemical Properties

• Describes matter based on its ability to change
  into a new substance with different properties

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Chemical Properties

• These properties can only be observed during a
  chemical reaction
• A chemical change has to take place in order to
  observe them!!!

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Chemical Properties

• Flammability
• Does it burn?
• How likely is it to burn?

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Flammability

• Can you think of any substances that are very
  flammable?
• Gasoline
• Paper
• Wood

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Flammability

• Can you think of any substances that are not
  flammable?
• Water

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Examples of Chemical Properties

• What is a reaction? What are some examples of
  types of reactions?
• Reactivity

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Examples of Reactivity

• Reacts with oxygen
• What happens when this substance reacts with
  oxygen?

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Reacting with oxygen

• Rust!
• When exposed to oxygen for long periods of time,
  metal will react with the oxygen to form RUST

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Examples of Reactivity

• Reacts with water
• What happens to the substance when it interacts
  with water?

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Examples of Reactivity

• Example
• Alka Seltzer and water

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Example 1

• You light a candle.
• Flammability or Reactivity?
• Flammability
• How do you know?
• It describes the substances ability to burn. A
  candle can burn easily, therefore it is
  flammable.

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Example 2

• Vinegar will react with baking soda.
• Flammability or Reactivity?
• Reactivity
• How do you know?
• Vinegar is reacting with baking soda and carbon
  dioxide is produced. This describes the
  interaction between two substances.

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Example 3

• Yeast acts on sugar to form carbon dioxide and
  ethanol
• Flammability or Reactivity?
• Reactivity
• How do you know?
• Yeast is reacting with sugar and forms two new
  substances, carbon dioxide and ethanol.

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Example

• When charcoal burns in a BBQ grill
• Reaction between Carbon and Oxygen
• Provides heat that cooks the dinner and gives off
  CO2

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Chemical Changes
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After a CHEMICAL CHANGE, a NEW substance is
produced with NEW properties. These properties
are different from the original substance!
A new substance is formed!
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Signs that a Chemical Change took place

• Production of a gas
• Often appearing as bubbles
• If it involves FIRE it involves gas (carbon
  dioxide in the smoke)

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Signs that a Chemical Change took place

• Change in temperature
• Such as the production or loss of heat

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Endothermic reaction

• A chemical reaction resulting in the loss of heat

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Endothermic reaction

• Example Ammonium nitrate and water in ice packs

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Exothermic reaction

• Exothermic reaction A chemical reaction
  resulting in the production of heat

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Exothermic reaction Example

• Example Hand warmers
• Iron reacts with oxygen to produce heat

Iron Oxygen ? heat
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Signs that a Chemical Change took place

• New color
• A chemical reaction results in a color change
• Metal and oxygen react to form RUST
• Color changes from silver to brownish red

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Signs that a Chemical Change took place

• Formation of a precipitate
• An insoluble solid that forms out of a water
  solution
• It forms because the solid does not dissolve in
  water

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Example 1 Burning wood
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Example 1 Burning wood

• What chemical property is present?
• Flamability
• What is the evidence of a chemical change?
• Production of a gas (SMOKE)
• Change in temperature
• Is it still the same substance?
• No! Ashes

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Example 3 Digestion of Pizza
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Example 3 Digestion of Pizza

• What chemical property is present?
• Reactivity
• What is the evidence of a chemical change?
• New substances with new properties
• Food is broken down by acid
• Is it still the same substance?
• No!
• Food is broken down into other substances (basic
  molecule types)

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Example 2 Rusting of Metal
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Example 2 Rusting of Metal

• What chemical property is present?
• Reactivity
• What is the evidence of a chemical change?
• Change in color
• Silver to reddish brown
• Is it still the same substance?
• No! Different properties

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Physical or Chemical??? Use the A-F cards to
separate the Physical Changes from the Chemical
Changes!
D. Rubbing alcohol evaporates from your hand E.
Hydrogen peroxide bubbles when you put it on a
cut on your leg F. Your friend melts some butter
for her popcorn
A. You cut a sheet of aluminum foil in half B.
You leave the milk on the counter all night and
discover it has soured in the morning C. Your
Mom lights a candle in a dark room