How to differentiate between physical and chemical properties

Alexis Roberts, Yary Urena, Quintessia Green, and Natalia Casas

Team 5 3rd Period

Physical Properties

Physical Characteristics can be observed and measured without changing the kind of matter being studied.

The following physical properties can used to help identify a substance.

Melting Point Melting Point- the

temperature at which a solid can change to a liquid.

The temperature at which a pure substance melts does not change under constant conditions.

The melting point of a pure substance can be used as a physical property.

Boiling Point

Boiling Point- The temperature at which a liquid boils

During the process of boiling, a substance changes from a liquid to a gas

Boiling begins when the liquid starts to form bubbles, which grow larger, rise to the surface and burst.

Boiling point is unchanging under constant conditions for a given substance, so it can used as a physical property

As long as the substance is boiling, the temperature remains constant

Density

Density- a property that describes the relationship between the mass of the material and its volume.

Substances that have higher densities contain more matter in a given volume

The density of a substance will stay the same no matter how large or small the sample of the substance is

For example, the density of lead is much greater than the density of aluminum

Color The color is used to identify

substances and other properties

The color itself is not a significant identifier of a substance

Whenever there is no color, it is also a physical property

Chemical Properties Chemical Properties are

also used as identifiers of a substance

These chemical properties can only be recognized whenever the chemicals react to each other or whenever they don’t

The chemical property of one substance usually involves its ability to react according to another specific substance or not

Reacting with Oxygen

An example of a chemical property is the ability of a substance to burn, this chemical property allows a substance to react quickly with oxygen to produce light and heat

This reaction occurs when iron begins to rust or apples turn brown

Reacting with Acids

When a substance has the ability to react with substance, it is also a chemical property

Some metals react with react with many acids to form compounds

Not all metals react with all acidsBases react with acids to form water

and to neutralize the acid

Physical ChangesPhysical changes do not change the

composition of a substance, only the physical properties.

Evidences of a physical change include…

Change in State of Matter When a substance changes from one state

to the other (liquid to solid, liquid to gas, etc.)the composition of the substance stays the same

Ex. Of change of state: melting ice cream When a substance changes from gas →

solid or solid → gas, that change of state is called sublimation

This is still a physical change because composition of the substances stays the same

Change in Shape and Size

When a substance changes in a size or shape (Cutting, tearing, dissolving, stretching, or wrinkling) its composition stays the same

EX: shredding paper, dissolving sugar in water, denting a piece of metal

Chemical ChangesChemical changes result in the

formation of one or more new substances with new chemical and physical properties.

Evidence that a chemical change may have occurred include…

Color Change

When a Substance changes color it shows the chemical reaction & how the chemical

composition has changed, for example: Iron turning reddish-brown when it rust

But it is possible that a substance can have a color change without a chemical change, for example: Putting food coloring in water

Temperature Change When 2 Substances Are Combined, There Could

Be An Increase Or Decrease In Temperature Like When Fire Burns Wood, The Temperature INCREASES

Its Is Possible To Have A Temperature Change WITHOUT A Change Without A Chemical Change Like Warming Up The Water In A Pond

Formation Of A Precipitation When TWO Solution Combine They May

Form A Solid Substance. This Solid Substance Is Called A .. PRECIPITATE & Indicates That A Chemical Change Has Occurred.

When Carbon Dioxide I Combined Is Combined With Aqueous Calcium Hydroxide (Limewater); Solid Calcium Carbonate (Chalk) Is Formed As The Particles, Appearing As Cloudiness In The Solution Or As A Sold Which Settles To The Bottom Of The Container.

Formation Of a Gas

When A Solid Or Liquid Substance Are Combined, They Form GAS BUBBLES

The Formation Of The Gas May Indicate That A Chemical Reaction Has Taken Place, Like When Vinegar Is added To Baking Soda, It Forms CARBON DIOXIDE BUBBLES

It Is Possible To Form Gas WITHOUT A Chemical Change, Like When Is Heated To Boiling