CHAPTER 15 SECTION 2 PROPERTIES OF MATTER

BY: BRANDON JONES, ASHLEY CASEY, KAYLEE COBB, MATTHEW WEATHERBY, TEA BRAGG, CAROLINE CAMPBELL, AND KAYLA CLARK

PHYSICAL PROPERTIES

Physical property- Any characteristic of a material that you can observe without changing the identity of the substances that make the material.

Appearance is the most obvious physical property. Example: for a soft drink in a cup, you could call it a brown colored liquid. You can measure

the temperature or volume, you could describe the appearance of the drink, you could describe the jar or the glass, each of these characteristics are physical properties of the drink.

Behavior- different states of matter have different physical properties that allow them to do different things

Example: a soft drink will bubble because of the carbonation Using physical properties to separate: physical properties such as magnetic attraction, can be

used to separate substances in a mixture. Example: removing the seeds of a watermelon can be easily done because of the physical

properties of the seeds and the rest of the watermelon

PHYSICAL CHANGE

Physical change- a change in size, shape, or state of matter

The identity remains the same: when a substance freezes, boils, evaporates, or condenses it under goes a physical change

All substances have distinct properties like density, heat, boiling, and melting points. These properties can be used to identify when a particular mixture contains substances which are not identified

Using physical change to separate: the property at boiling point is a type of distillation

Distillation- process for separating substances in a mixture by evaporating a liquid and re-condensing it

Two liquids that have different boiling points can be separated in a similar way; often used in industry

If you break a stick you have changed its shape and size, but you have not changed the identity of the materials that make up the stick

CHEMICAL PROPERTIES AND CHANGES

Chemical property- characteristic of a substance that indicates whether it could undergo a certain chemical change

The tendency of a substance to burn, or its flammability is an example of a chemical property because burning produces new substances during a chemical change.

Many substances used around the home, such as lighter fluids, are flammable

DETECTING CHEMICAL CHANGE

Chemical Change- the change of one substance into another substance

In some chemical changes a rapid release of energy is a clue that changes are occurring

Heating, cooling, or formation of bubbles or solids are indicators that a reaction is taking place

Using Chemical Change to Separate-

Tarnish is a chemical reaction between silver, metal, and sulfur compounds

Silver, metal, sulfur in the air result in tarnish

WEATHERING: CHEMICAL & PHYSICAL CHANGE Weathering- The forces of nature shape earths surface

Example of weathering- Physical change: large rocks can spilt when water spreads into small cracks, freezes and expands. However the smaller pieces of the newly exposed rock still have the same properties.

Example of weathering- Chemical change: solid calcium carbonate, a compound found in limestone, does not dissolve easily in water. However, when the water is even slightly acidic, as it is when it contains some dissolved carbon dioxide, calcium carbonate reacts. It changes into a new substance, calcium hydrogen carbonate, which does dissolve in water. This change in limestone is a chemical change, because the identity of the calcium carbonate changes

Below in the center is a picture of limestone in the Grand Canyon. It is stained red from iron oxide impurities.

THE CONSERVATION OF MASS

Law of Conservation of Mass- mass of all substances that are present before a chemical change equal the mass of all substances that remain after the change.

Mass is not lost or gained during chemical change.

This reaction appears to be destroying this log. When it is over, only ashes will remain. Yet you

know that no mass is lost in a chemical reaction.

DO NOW:

Finish completing the assessment worksheet.

Write down as many facts as you know on a separate sheet of paper.

Whoever has the most amount of informational facts (i.e.- the information is actually on topic) as you can in 3 minutes gets a piece of candy.