Properties of Matter Chapter 17 Section 2 Physical Properties and Changes.

Physical Properties Any characteristic of a material that you can observe or attempt to observe without changing the identity of the substance that makes up the material is a physical property.

Examples Physical changes include: Color Size Shape Melting point Boiling point

Explanation What an object looks like, i.e., an apple, tennis ball, a rock. – Physical Description Appearance – How the object reacts with the things around it. If you knocked over corn syrup, the high viscosity in the liquid is a physical property.

You can use the physical properties to separate mixtures. Example: Different seeds – the filling in a Twinkie- or eating the icing on a cake but not eating the cake itself. (Thibodeaux’s 5th Birthday)

The changes in the states of matter are examples of physical change. The changes in the states of matter (solid  liquid  gas) are examples of a physical change. When a substance freezes, boils, evaporates, or condenses, it undergoes a physical change.

More Physical Descriptions A change in: Size Shape State of matter All are considered physical change.

Here’s what I am trying to say! There may be changes, but the identity of the element or compound does not change.

Example: Water – If it freezes, is it still water? If it is boiling, is it still water? If it is in the liquid state, is it still water? They are different sizes, shapes, and states, but still high quality H2O!!!

Example #2 IRON – When you heat iron, it turns red or white. Even though there is a color change, it is still iron.

Distillation Distillation is a process for separating substances in a mixture by evaporating a liquid and recondesing its vapor. It is usually done in a laboratory using an apparatus. The liquid is boiled then condensed in a tube leaving the solid material behind.

Picture of Distallation

Water is not all equal. This is how some water purifiers make there distilled water. There are water plants next to the ocean that takes the sea water, distills it, leaving the salt behind and fresh purified water to be sold.

Example: Two liquids with different boiling points can be separated this way. This is how they separate natural gas from oil.

Chemical Properties and Changes The tendency of a substance to burn, or its flammability, is an example of a chemical property because burning produces: A New Substance!!!!!!!! During a chemical change.

Chemical Property A chemical property is a characteristic of a substance that indicates whether it can undergo a certain chemical change.

Examples: Lighter fluids Medicine – bottles are dark because light will change them chemically if exposed too long.

Example #2 If you burn something, the bad odor is the result of a chemical change. If you smell rotten eggs The rust on a bike – New substance = chemical change (write this down)

This is what I am trying to say!! Easy way to remember: If you can’t change it back to its original state, then it was a chemical change, but if you can, then it was a physical change.

Chemical Changes A rapid release of energy Heat, Light, and Sound are all clues that changes have occurred.

Chemical Changes Chemical Changes clues: Heat Cooling Or the formation of bubbles The creation of solids in a liquid All these are helpful indicators that a reaction has taken place

Weathering Question – Are the forces that cause rocks to split, deep canyons to be carved out, sand dunes shift, or curious limestone formations caused by physical weathering or chemical weathering.

Physical Large rocks split when water seeps into the small cracks and freezes. Remember what happens to water when it freezes. It exapands

Physical The new rock that is exposed is the same as the original. It was physical

Chemical Solid calcium carbonate does not dissolve easily in water. However, when the water is slightly acidic, calcium carbonate reacts. It changes into a new substance, calcium hydrogen carbonate, which does dissolve in water. This is considered a chemical change because the identity of the calcium carbonate changes.

The Conservation of Mass According to the Law of Conservation of Mass, the mass of all substances that are present before a chemical change equals the mass of all the substances that remain after the change.

Matter is neither created nor destroyed. It just changes in a chemical reaction.