Absolute zero is the lowest temperature possible. At a temperature of absolute zero there is no motion and no heat. Absolute zero occurs at a temperature of 0 degrees Kelvin, or -273.15 degrees Celsius, or at -459o degrees Fahrenheit.

A vacuum pump is a device that removes gas molecules from a sealed volume in order to leave behind a partial vacuum .

The first vacuum pump was invented in 1650 by Otto von Guericke .

In everyday usage, vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than atmospheric pressure. The word comes from the Latin term for "empty".

A perfect vacuum would be one with no particles in it at all, which is impossible to achieve in practice. Physicists often discuss ideal test results that would occur in a perfect vacuum, which they simply call "vacuum" or "free space", and use the term partial vacuum to refer to real vacuum.

Light bulbs contain a partial vacuum, usually backfilled with argon, which protects the tungsten filament.

Single-barrel vacuum pump milking machine

Dry Ice is frozen carbon dioxide.......   .......a normal part of our earth's atmosphere.

It is the gas that we exhale during breathing and the gas that plants use in photosynthesis. It is also the same gas commonly added to water to make soda water.

Dry Ice is particularly useful for freezing, and keeping things frozen because of its very cold temperature:

-109.3°F or -78.5°C.

Dry Ice is widely used because it is simple to freeze and easy to handle using insulated gloves.

Dry Ice changes directly from a solid to a gas -sublimation- in normal atmospheric conditions without going through a wet liquid stage.

Therefore it gets the name "dry ice."

Sublimation is the transition of a substance from the solid phase to the gas phase without passing through an intermediate liquid phase.

As a general rule, Dry Ice will sublimate at a rate of five to ten pounds every 24 hours in a typical ice chest.

This sublimation continues from the time of purchase, therefore, pick up Dry Ice as close to the time needed as possible. Bring an ice chest or some other insulated container to hold the Dry Ice and slow the sublimation rate.

Dry Ice sublimates faster than regular ice melts but will extend the life of regular ice.

CNS 8 Investigation – Proving Gas is Matter Observation (prior knowledge)What is matter?

What is the Law of Conservation of Mass?

Problem – How can gas be weighed and does gas have mass?

Hypothesis – If gas has mass, then a chemical reaction that produces gas will have LESS mass after the reaction than before the reaction.

CNS 8 Investigation – Proving Gas is Matter Observation (prior knowledge)What is matter?Matter is anything that has mass and takes up space.

What is the Law of Conservation of Mass?

The Law of Conservation of Matter states that you can never create nor destroy matter. You can change the matter, but not create nor destroy it.

Problem – How can gas be weighed and does gas have mass?

Hypothesis – If gas has mass, then a chemical reaction that produces gas will have LESS mass after the reaction than before the reaction.

Experiment -

Materials: balance, 50 mL beaker, 15 shell pieces, 30 mL hydrochloric acid solution, forceps, goggles

Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid .

Concentrated hydrochloric acid (fuming hydrochloric acid) forms acidic mists. Both the mist and the solution have a corrosive effect on human tissue, with the potential to damage respiratory organs, eyes, skin, and intestines.

Eye goggles must be worn throughout the entire lab!

Wash your hands immediately with soap and water, if you get the HCl on your skin.

Procedure: WEAR SAFETY GOOGLES1. Tare the paper.

2. Find the total mass of the acid, beaker, paper and shell before the reaction.

3. Subtract the mass of the paper from your total. 4. React 15 pieces of shell with 30 mL of acid.

5. Using a forceps, drop the shell pieces, one by one, into the acid.

6. Record all your observations.

7. Compare that mass to the total mass after the reaction.Show all your math work.8. Clean your area up, use the dump bucket to get rid of material, wash your beaker in the wash bins.

Observations - Record all observations of the reaction neatly.

Total mass of all materials= _________ - mass of paper = _________Total mass after reaction = ____________________Calculate the mass of the gas produced = _____________________

Conclusion - Was your hypothesis correct? How did you know it was a chemical reaction?

Chemical Changes….

Are changes that cause a NEW material to form.

The original material cannot easily be recovered.

There is a chemical reaction.

SIGNS OF A CHEMICAL REACTION:

Unexpected color changeBubbling or fizzing (which means a gas is forming)LightSmokeTemperature changeA solid (precipitate) may form when two liquids are mixed

Desublimation

EvaporationFr

eezing o

r Solid

ifica

tion

Melting or L

iquefacti

on

Sublimation

Condensation