by sanaa ahmed. main idea physical and chemical properties are characteristics to describe,...
Post on 22-Dec-2015
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Main Idea
• Physical and chemical properties are characteristics to describe, identify, and classify matter
• Matter is anything that has mass and volume
Using Your Senses
• Every object or material you can think of is a form of matter
• Every sample of matter has properties that describe it
• Properties can also be used to help identify pure substances; elements and compounds
PHYSICAL PROPERTIES
Physical Propertie
s
Color, Shape, Luster, Texture
Mass, Volume, Density
State Of Matter,
Solubility, Conductivit
y
Boiling Point,
Melting Point
Malleability,
Ductility
Chemical Property• The ability or tendency
of a material to change its chemical makeup
• Materials are made up of atoms and molecules. When the arrangement of the atoms and molecules change, a new material is formed
• The new material has a different identity and different properties
MASS• Mass is the measure
of the amount of matter in an object or a material
• It can be measured in grams or kilograms
• A large object contains more matter than a smaller object, so the larger object has greater mass
VOLUME• Volume is the amount
of space a sample of matter takes up
• The volume of a solid can be measured in cubic centimeters
• Liquid volumes are measured in liters or milliliters
DENSITY• The density of a
material is its mass per unit volume
• To find the density of a sample, measure its mass and its volume and divide
• All samples of a pure substance kept under the same conditions have the same density
STATES OF MATTER
Solids are rigid and have a definite shape and volume.
Liquids take the shape of their container, but keep the same volume.
Gases have no definite shape or volume.
Another physical property is state of matter. The three familiar states are solid, liquid, and gas.
MELTING POINT• When enough energy is added to a solid, it melts to
form a liquid. The temperatures at which a solid substance changes to a liquid is called its melting point
• The chemical element with the highest melting point is Tungsten at 4488 Kelvin (4215 °C, 7619 °F) making it excellent as filaments in light bulbs
BOILING POINT• When enough energy is added to a liquid, it changes
into a gas. The temperature at which this happens is called the boiling point
• The boiling point of a liquid varies depending upon the environmental pressure
• The higher the pressure, the higher the boiling point
SOLUBILITY • The measure of how much
of one substance can dissolve in another is called solubility
• Solubility of a substance depends on its physical and chemical properties as well as temperature, pressure and pH of the solution
• Saturation point is a stage at which no more of one substance can be dissolved into a solution
CONDUCTIVITY• The conductivity of a
material is its ability to carry energy
• Electrical conductivity refers to carrying electricity
• Thermal conductivity refers to carrying heat
• Most metals are good conductors of heat and electricity
SOME MORE PROPERTIES OF
MATTERMALLEABILITY• Is a physical property of
matter, usually metals• Ability of a metal to
bend or be hammered into thin sheets without breaking
• Some examples are gold, iron, aluminum, copper, silver and lead
• Malleable metals are used to make jewelry, utensils, cans, foils etc.
DUCTILITY• Ability of a metal to be
stretched into a wire
• Some metals can either have good malleability or ductility or both
• Gold has high malleability and ductility but lead has high malleability but low ductility
• Copper is highly ductile and is used to make copper wires for electrical purposes
RADIOACTIVITY• The emission of radiation
from an atom with an unstable nucleus.
• Chemical property of elements on periodic table with no stable isotopes
• The radiation can be emitted in the form of a positively charged alpha particle, a negatively charged Beta particle, or gamma rays.
• Uranium, Radium, Plutonium
USES OF RADIOACTIVE
ELEMENTS• Uranium and Plutonium are used to generate electricity in nuclear power plants
• Tritium and radium glow because of their radioactive decays. Tritium is used in small quantities in small vials on watch hands and to mark the hour positions on watch dials. Radium is not used any more
• Radioactive material is essential in medical care. Since radiation is relatively easy to detect, physicians give patients fairly harmless radioactive pills to find out whether anything is wrong or blocking the body's normal digestive functions or to test new drugs
DANGERS OF RADIOACTIVE
ELEMENTS• Scientists have long known that radiation can cause cancer in humans. Radioactive energy waves are so small that they can pass through the body and harm a person's genetic make up found in their DNA
• The atomic bomb, for example, takes advantage of clusters of uranium and plutonium exploding on top of each other to create a massive reaction
• During the second world war, explosion of atomic bomb in Japan caused lot of destruction
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