Kinetic Molecular Theory & Heat and States of Matter Chapter 15 Kinetic Molecular Theory & Heat and States of Matter

Some Amazing Things

Kinetic Theory

Kinetic Theory All matter is composed of tiny particles.

Kinetic Theory All matter is composed of tiny particles Atoms

Kinetic Theory All matter is composed of tiny particles Atoms Molecules

Kinetic Theory All matter is composed of tiny particles Atoms Molecules Ions

Kinetic Theory These tiny particles are in constant motion. Liquid Gas Solid

Kinetic Theory Collisions between moving particles are perfectly elastic. In an elastic collision there is no net change in kinetic energy.

Pressure Pressure depends on two factors Force Area Pressure = Force

Examples of Pressure

Examples of Pressure

Examples of Pressure The origin and age of snowshoes are not precisely known, although historians believe they were invented from 4,000 to 6,000 years ago.

Examples of Pressure It is illegal to wear high heels at many archaeological locations. Pointy heels can damage these ancient sites. Experts have determined that high heels can transmit more pressure per square inch than an elephant walking on the same surface.

Gas Pressure

Temperature How hot or cold Average kinetic energy

How do we lower temperature? We slow down the particles.

Absolute Zero K = °C + 273 °C = K - 273

Kinetic Energy KE = ½ mv2 When considering kinetic energy we must consider two factors. Mass Velocity

New Discipline System

“Old Fashioned Discipline”

New Discipline System “Old Fashioned Discipline”

I’m Here for Class Mr. Stillwell.

Where’s Mr. Stillwell?

Do Not Touch HCN H2S

Stink Die Or

Stink And Die

Do Not Touch HCN H2S

Do Not Touch H2S 34 amu HCN 27 amu

Heat & States of Matter

At room temperature most elements are solids. The gases are hydrogen, nitrogen, oxygen, fluorine, chlorine and the noble gases. There are two liquids: bromine and mercury.

The state of matter is determined by two factors.

1. Attractive forces between the particles of the material. Liquid Gas Solid

2. Temperature (Average Kinetic Energy)

At room temperature which factor determines the state of an element?

Transitions between the states of matter We can change the state of matter that a substance exhibits by adding/removing heat.

Heat Heat is thermal energy that flows from something warmer to something cooler.

Transitions between the states of matter

How many states of matter exist? 5

Plasma: The fourth state of matter

Transitions between the states of matter If we heat a gas to a high enough temperature it becomes a plasma.

Plasma A plasma is a super heated ionized gas. Normally requires extremely high temperatures to form. It consists of electrons and positively charged gas particles.

Plasma Plasmas are the most common state of matter in the universe. It is estimated that 99% of the visible universe is plasma.

Plasma Plasmas do not occur as frequently on earth.

“Cold” Plasmas

“Cold” Plasmas Plasmas can exist at much lower temperatures than normal in a vacuum.

The Fifth State of Matter Bose – Einstein Condensate (BEC)

Bose – Einstein Condensate In the 1920s, Satyendra Bose and Albert Einstein, predicted this new state of matter. However they didn't have the equipment and facilities to make it.

Bose – Einstein Condensate In 1995, three scientists, Karl Weiman, Wolfgang Ketterle and Eric Cornell finally created this new state of matter. They were awarded the Nobel Prize in 2001.

Bose – Einstein Condensate If plasmas are super hot and super excited atoms, the atoms in a Bose-Einstein condensate (BEC) are total opposites. They are super-unexcited and super-cold atoms.

The Fifth State of Matter The BEC happens at super low temperatures. At zero Kelvin all molecular motion stops. At only a few billionths of a degree above absolute zero, you can create a BEC with a few special elements. Cornell and Weiman did it with Rubidium.

Time for a Chemistry Joke

Bose – Einstein Condensate As temperatures get to within a few billionths of a degree of absolute zero atoms begin to “clump”. The result of this clumping is the BEC. A group of atoms becomes one "super atom." There are no longer thousands of separate atoms. They all become indistinguishable from one another and become one “super atom”.

What does a Bose Einstein Condensate Look Like? It looks like a dense little lump in the bottom of the magnetic trap/bowl. Picture a drop of water condensing out of damp air. When it first forms, though, the condensate is still surrounded by the normal gas atoms, so it looks a bit like a pit inside a cherry.

Bose-Einstein Condensation at 400, 200, and 50 nano-Kelvins When matter gets cold enough a dense blob forms in the center. You can see this in the pictures of Cornell and Wieman’s actual data as they cool the atoms from 400 billionths of a degree above absolute zero down to 50 billionths. Bose-Einstein Condensation at 400, 200, and 50 nano-Kelvins

Homework Worksheet #34 “Temperature and Particle Motion” (due tomorrow). Worksheet Chapter 15 (due in 2 days). Test Chapters 12 – 14 Wednesday.