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How to differentiate between physical and chemical properties. Alexis Roberts, Yary Urena , Quintessia Green, and Natalia Casas Team 5 3 rd Period. Physical Properties. - PowerPoint PPT Presentation
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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