Agenda Demonstration  Water Vapor in a Can Demonstration Discussion Introduction to Gasses Ideal Gas Laws

Demonstration Procedure 1. Add a small amount of water to the bottom of a coke can. Can About a Tbsp of H 2 O

Demonstration Procedure 2. Heat can until steam begins to come out. Heat Can with Water In It Water Vapor (steam)

Demonstration Procedure 3. Use tongs to invert can into cold water. Can with Water Vapor In It Cold Water

Demonstration Classwork 1.On notebook or scratch paper, write down what you think will happen to the can and why. 2.Discuss with your group. Save paper for later.

Demonstration: Discussion What happened to the can? Why?

Demonstration: Discussion 1.Atmospheric Pressure Air molecules constantly bombard all objects. The more frequently they hit an object, the greater the pressure they exert on an object. An object such as an open container experiences the same atmospheric pressure both inside and out.

Demonstration: Discussion 2.Changes of State A liquid such as water may be converted to a gas by heating it This conversion is a physical change of state The molecules of the gas will occupy more space than they did in the liquid Water molecules in the liquid state are in close contact Water molecules in the gaseous state are separated from each other

Demonstration: Discussion 3.Gases Upon cooling a gas may be converted to its liquid state Upon cooling, steam condenses to liquid water Liquid water occupies less space than steam

Demonstration: Discussion Conclusions When the pressure outside an object is greater than the pressure inside, a change will occur The change is reversible that is, If the can could be sealed and reheated, it would regain its shape when the two pressures become equal again

Demonstration: Discussion Can With Equal Pressures Both Inside And Outside

When Water Condenses from a GAS to a LIQUID Pressure OUTSIDE is Greater Than Pressure INSIDE, CAN COLLAPSES!!! Demonstration: Discussion

Demonstration Classwork 1.How did what happened compare with your predictions? Beneath your predictions, explain in your own words what happened to the can. 2.Discuss with your group.

Gases and The Gas Laws The density of a gas decreases as its temperature increases.

Earth as a Closed System

The Earth’s Atmosphere 78% Nitrogen 20% Oxygen 1% Argon 0.03% CO 2 Trace Elements Helium Nitrogen Oxygen Water vapor Argon Neon Carbon dioxide Air

The Earths Atmosphere Zumdahl, Zumdahl, DeCoste, World of Chemistry  2002, page 309

The Earth’s Atmosphere From Space If the Earth were the size of a beach ball, the atmosphere would be roughly as thick as a sheet of paper.

Gases Dissolved in Water

Natural Gas