Physical Vs. Chemical Properties & Changes

What is a Property? A property is a quality specific to a substance that helps us to classify or identify the substance.

There are 2 kinds of properties: Physical Property & Chemical Property

Physical Property Physical Property- a characteristic of matter that can be observed without producing a new kind of matter. Color, size, texture, and shape are examples of physical properties. Physical properties help us to distinguish one kind of matter from another. Two more examples of Physical properties are Melting and Boiling points. (ex., silver)

More Examples of Physical Properties Density- how tightly packed matter is in a given amount of space (D= m/v) Malleability- the ability to be hammered into a shape. Viscosity- a fluids resistance to flow. Ductility- the ability to be pulled into thin wires.

Chemical Property A chemical property is a description of how a certain kind of matter reacts. Does the matter combine with another form of matter to produce a new kind of matter? Does the matter break apart to produce a new kind of matter?

Example of a Chemical Property When Oxygen( a kind of matter) combines with aluminum (also a kind of matter) it has the ability to form a coating. This coating is a new kind of matter with different physical and chemical properties.

There are four basic Chemical Properties: The ability to react with acid The ability to react with oxygen(burning and rusting) The ability to react with electricity The ability to react with another substance

Copy the following and write down whether it is physical or chemical next to it:

Physical or Chemical? Blue Color Flammability Reacts with Acid to form H2O Solubility Sour Taste Melting Point Odor Reacts with water to form a gas

What is the difference between a Property and a Change? A property is the description/characteristic of matter and/or ability to change. A Change is the actual change or reaction that occurs.

A Physical Change A Physical Change is the change of some physical property of matter (ex.size, shape, texture, etc…) But does not change the chemical identity of the matter. For example, think about a silver spoon or an apple.

Chemical Change A chemical change occurs when the chemical identity of the matter is changed. It takes a reaction to change the identity!! You know a chemical change has occurred when it is accompanied by … the formation of gas a change in color a change in temperature

Two types of Chemical Changes are: composition and decomposition

Composition Reaction A composition reaction involves combining two forms of matter to produce a new kind of matter. For example, when sodium is combined with chloride…salt is formed.

Decomposition A Decomposition reaction involves combining one type of matter with something else (matter or energy). The matter breaks down and forms a new kind of matter. Think about wood burning.

An Example of a Composition Reaction: The iron metal of nails combined with oxygen forms a reddish-brownish solid called rust. Rust is a new kind of matter with its own set of physical and chemical properties.

Phases of Matter The phases of Matter are a physical property and change of matter. –Think about water for example. There are four different phases of matter!

Plasma Plasma is a phase of matter that is similar to a gas. Unlike gas, Plasma is produced by burning gases at very high temperatures, as in the sun and other stars. It may also be produced if the matter is exposed to a significant electrical current.

Solid A solid has definite shape and definite volume. Under regular circumstances, the shape and volume of solids do not change. Molecules vibrate in place

Liquid A liquid has a definite volume, but not a definite shape. Liquids take the shape of the container they are in, but the volume remains the same. Molecules have a rapid, random motion.

Gas A Gas does not have a definite shape or a definite volume. Like liquids the gas takes the shape of its container. (Remember the balloon and air?) Unlike Liquids the volume does not necessarily stay the same. Molecules have very rapid, random motion.

There are several changes in phase and all are physical changes. Use the following list as key words for physical properties and changes!!! *melting- *freezing- *evaporating- *sublimation- *boiling- *vaporization- *condensation-

Two Types of Solids: A Crystalline solid - the molecules are arranged in a fixed, regular pattern Solids that have such a repeating pattern are called crystals. An Amorphous Solid - the molecules are not arranged in a fixed regular pattern; they are arranged in a random pattern. Solids that have a random pattern are called amorphous.

Compound vs. Mixture Compound is a substance that is made up of two or more elements chemically bonded together. Mixture is a substance that is made up of two or more elements, but the elements are not chemically bonded together.

Two types of mixtures!!! Homogeneous and Heterogeneous Let’s use the prefixes to help us remember which one is which!!! Remember, Prefixes bring with them a meaning to whatever we attach them to Homo vs. Hetero Homo means same Hetero means different

Homogeneous- a mixture in which substances are evenly distributed throughout the mixture. It all looks the same!!! Example, Milkshake Heterogeneous Mixture- a mixture in which substances are unevenly distributed throughout the mixture. You can see the different parts!!! Example, Fruit Salad

Physical vs. Chemical 1.cuts- 2.boils- 3.burns- 4.corrodes- 5.smash- 6.rusts- The following are key words that represent either physical or chemical changes. The letter “p” identifies a physical change key word and the letter “c” identifies a chemical change key word:

7. evaporates- 8.reacts- 9.hammering- 10.viscosity- 11.spoiling- 12.folds- 13.decomposes- 14.paint- 15.mixing- 16.combining-

17. dissolve- 18. luster- 19. bleach- 20. density- 21- bonds with- 22. malleability- 23. ductility- 24. mixture- 25. compound-

Are we finished? You bet we are!!!!!