Matter Chapter 9.2 and 18

What do all of these items have in common?

Matter Anything that takes up space Can be a solid, liquid or gas

What is dry ice? CO2 that is below -78○C (-108.7 ○F) that has formed a solid

Where do we find CO2? Soda Carbon cycle 0.038% of air we breathe Paint ball guns Fire extinguishers

Why is it dangerous to touch dry ice with bare hands? Frostbite or Tissue damage

Observe the dry ice in the front of the room. Write down your observations…

Three states of matter Solid Liquid Gas

Three States of Matter Solid State 9.2 Particles of a solid are packed closely together and are constantly vibrating in place Attractions between particles are strong Solids have a fixed volume and shape

States of Matter 9.2 Liquid State Attractive forces are strong enough to cause particles to cling together Liquids have a definite volume, but not a definite shape.

States of Matter 9.2 Gas State In a gas the forces between particles are so weak that the particles no longer cling together. Gases do not have a definite shape or volume.

What is the difference between a liquid and a gas? You can see a liquid but you cannot see a gas.

If you cannot see a gas, what is the fog coming off the dry ice? What appears to be fog or clouds, you are seeing little liquid water droplets. They float like a gas and don’t feel like a liquid because they are 1/1000 the size of raindrops.

9.2 Changing States Adding or removing energy can cause matter to change states Melting – solid to liquid Freezing – liquid to solid Vaporization Evaporation – liquid to gas at surface Boiling – liquid to gas throughout Condensation – gas to liquid Sublimation – solid to gas