Chemistry chapter 2
Download
1 / 15

Chemistry Chapter 2 - PowerPoint PPT Presentation


  • 59 Views
  • Uploaded on

Chemistry Chapter 2 . Changes in Matter Physical and Chemical Changes. Types of changes in matter:. Physical Change. Chemical. Physical change alters the form of a substance but does not change it to another substance. The substance has the same properties as the starting material

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Chemistry Chapter 2 ' - barbie


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Chemistry chapter 2

Chemistry Chapter 2

Changes in Matter

Physical and Chemical Changes


Types of changes in matter
Types of changes in matter:

Physical Change

Chemical

  • Physical change alters the form of a substance but does not change it to another substance. The substance has the same properties as the starting material

    • Tearing paper, bending a nail, spinning wool into yarn

  • When a substance undergoes a chemical change, it is changed into a different substance with different properties

    • Burning wood turns it into carbon dioxide and ash

Both changes involve energy!!


Changes in matter involve energy
Changes in matter involve energy:

Every substance contains energy from the movement of its particles called THERMAL ENERGY

The higher the temperature of a substance, the greater its thermal energy.

Another form of energy comes from the chemical bonds within matter : CHEMICAL ENGERY

Matter changes whenever energy is added or taken away!

The LAW OF CONSERVATION OF ENERGY states that in every physical change and chemical change the total amount of energy stays the same.


Melting
Melting

  • Change in state from a solid to a liquid

  • Ice cube melting – energy to melt comes from the air in room. Added thermal energy makes the water molecules vibrate faster, which raises their temperature. Eventually water molecules vibrate so fast they break free from their position in ice crystals.

Click for melting chocolate video

Click for melting gold video


Freezing
Freezing

  • Change in state from a liquid to a solid

    • Water turns to ice – when water is placed in the freezer the water loses energy to the cold air in the freezer. Water molecules move more slowly. When the temperature reaches 0°C, the molecules are moving so slowly that they form regular patterns which form ice.

Water freezing video (click ice cube tray)

Click for video


Condensation
Condensation

  • Change in state from a gas to a liquid

  • Occurs when a gas loses enough thermal energy to become a liquid

    • Clouds, breath on a mirror, fog, steam

Condensation video (click on glass)

Condensation on window

Condensation on soda can

Condensation on mirror


Vaporization –change in state from a liquid to a gasOccurs when a liquid gains enough energy to become a gas

Evaporation

Boiling

  • When vaporization takes place only at the surface of the liquid

    • A puddle drying up after a rainstorm

    • Beads of sweat evaporate off your skin

  • When vaporization takes place inside the liquid as well as at the surface

    • Water boiling on stove

Click for video

Click for video


Sublimation
Sublimation

  • Change in state from a solid to a gas

  • Occurs when a solid gains enough energy to become a gas. Particles DO NOT pass through the liquid state at all.

    • Dry ice, moth balls, snow on a cold day

Sublimation of Dry ice

(click to watch video)


Changes in state
Changes in state

http://itl.chem.ufl.edu/2045_s00/lectures/lec_f.html


Changes of state
Changes of State

http://itl.chem.ufl.edu/2045_s00/lectures/lec_f.html


Chemical changes chemical reaction
Chemical Changes (Chemical Reaction)

  • One substance breaks down into two or more other substances

    or

  • Two or more substances combine forming one or more new substances.

  • NEW SUBSTANCES ARE PRODUCED


Signs of a chemcial reaction
Signs of a chemcial reaction

  • Signs of chemical reactions

    • Bubbles (gas produced)

    • Light produced

    • Color change

    • Solid (precipitate) formed

    • Odor change

    • Heat


Examples of chemical changes
Examples of chemical changes….

  • Baking soda and vinegar

    • http://www.youtube.com/watch?v=nrTpubja0z8

  • Sodium Chloride

    • http://www.youtube.com/watch?v=Ftw7a5ccubs&feature=related


Is this a chemical or physical change
Is this a chemical or physical change?

  • Mentos and diet coke

    • http://www.youtube.com/watch?v=LjbJELjLgZg&feature=related


Non newtonian fluids
Non-Newtonian Fluids

  • Has properties of both solid and liquid

  • Examples: Oobleck, PVA slime, and silly putty

Click for video


ad