Transcript
MATTER AND MATERIAL
THOBILE NKOSI
201109811
1. INTRODUCTIONEverything has an origin. Objects that we use are made out of different kind of matter and materials.In this unit we are going to see the ways we find matter in our everyday life, characteristics of different materials and how can we save materials by recycling.
WHAT IS MATTER?
Matter is everything around you. Matter is formed by groups of atoms that form molecules. The atoms that are in the molecules stay linked because they share or change electrons.
Molecules are formed by 2 or more atoms of 1 or more elements. For example: a water molecule is formed by 2 atoms of hydrogen and 1 atom of oxygen.
ATOM MOLECULE
Andries p 87
The particlesin solids,
liquids, andgases:
Andries p 87
Three phasesof matter
MATTER STATES SOLID
Solids have a defined shape and volume, molecules are so close together that they form a hard structure.
Examples: Wood, stone... EXPLANATION:When you take a stone, wood, plastic…and change it from one place to another, they don´t change size or shape. Shape and size of solids are the same as long as we don´t transform them by carving, cutting, hitting…
SOLID’S MOLECULES
Molecules in solids are tightly together. They vibrate but they can´t move.
MATTER STATESLIQUID
Liquids fill up the shape of their containers. Liquids can flow into any container and change their shape, while they stay with the same volume.
Examples: Water, oil, milk, juice...
EXPLANATION:When you pour water into a glass, the water gets the shape of the glass. If you change that water into a bowl, it gets the shape of the bowl. The amount of water doesn´t change, only the shape.
LIQUID’S MOLECULESMolecules in liquids are close together. They move and slide past each other.
MATTER STATESGAS
Gases don´t have a defined shape or volume. They take the shape and the size of their container. Gases are as big as their containers.
Examples: Hydrogen, oxygen...
EXPLANATION:Gases are all around us. They move and grow as long as they have space to do it.
GAS’ MOLECULESMolecules in gases are separated and free. They move around and vibrate at high speed.
MATTER STATESMATTER STATE CHANGES
SOLID
GAS
LIQUID
CONDENSATION
EVAPORATION
SOLIDIFICATION
MELTING
SUBL
IMAT
ION
Atomic
bonds
Chem
ical b
ond
s
Everything consists of
of elements (except group 8) are not found alone.
are components of larger units bonded chemically.
DocScientia p 14
A chemical bond occurs when bondtogether to form a new substance withnew properties and in so doing have a
noble gas electron structure and a lowerEp.
DocScientia p 14 Chemical bonds
Bond
ing
mod
els
DocScientia p 14
A modeldescribes an ideaor thought
Covale
nt b
ond
Between non-metalse- are sharedSmallest particle is a molecule.
have half-filled orbitals that overlap to form a filled orbital
e-negativity must be the same or the diff. < 1,9Polar ornon-polarbonds form
WHAT IS A CHEMICAL?
Any substance that has a definite composition or is used or produced in a chemical process.
Sugar is an example of a chemical
MATTER
Anything that has mass and occupies space
All matter is composed of atoms
Atom: Extremely small chemically indivisible particle
Atom is Greek for “that which cannot be divided”
Greek philosopher Democritus is given credit for idea
Modern science can now divide an atom, so new definition includes chemically indivisible
An atom cannot be divided and retain it’s chemical properties
THREE MAJOR CLASSES OF ELEMENTS
Metals- located on the left of the Periodic Table- most of the elements
Non-Metals- located on the right of the Periodic Table
Metalloids- on the zigzag line between Metals and Nonmetals- have properties that are skewed- i.e.…Silicon is conductive
You will have to memorize the symbol and element name for approximately 40 common elements
MORE WAYS TO DESCRIBE MATTER
Element: any substance that cannot be broken up into simpler substances by chemical means
silver, copper, hydrogen, oxygen nitrogen
Compound: a substance formed when atoms of two or more elements join together
H20 (water), CO2 (carbon dioxide)
Mixture: a material of two or more substances that are not chemically bound to each other and can be separated
Blood: water-based mixture including
Proteins, sugars, salt, oxygen, carbon dioxide
PROPERTIES OF METALSMetals are good conductors of heat and electricity
Metals are malleable (can be shaped)
Metals are ductile (can be drawn into wires)
Metals have high tensile strength
Metals have luster (shiny)
PROPERTIES OF NONMETALS
Carbon, the graphite in “pencil lead” is a great example of a nonmetallic element.
Nonmetals are poor conductors of heat and Electricity
Nonmetals tend to be brittle
Many nonmetals are gases at room temperature
WHAT IS NOT MATTER?
• Light
• Electricity
• Sound
Fixed composition
Cannot be separated into simpler substances by
physical methods (physical changes)
Can only be changed in identity and properties by
chemical methods
Properties do not vary- Unique Density, Constant
Boiling and Melting Points
Compounds
Chemically joined elements- Can be decomposed into simpler substances by chemical changes, always in a definite ratio
Elements Cannot be
decomposed into simpler substances by chemical changes
SECTION 3-4
Compounds (cont.)
• The properties of a compound are different from its component elements.
SECTION 3-4
Compounds
• A compound is a made up of two or more elements combined chemically.
• Most of the matter in the universe exists as compounds.
• Table salt, NaCl, and water H2O, are
compounds.
SECTION 3-4
Compounds (cont.)
• This figure shows electrolysis of water to form hydrogen and oxygen.
Variable compositionComponents retain their characteristic propertiesMay be separated into pure substances by physical
methods sifting, evaporation, magnetism, etc…Mixtures of different compositions may have widely
different propertiesDo NOT have definite boiling/melting points
Homogenous mixtures look the same throughout but can be separated by physical means
Examples: salt water, soda
Have the same composition throughoutComponents are indistinguishableCan exist between all phases of matter:
air (gases) brass (alloy- blend of multiple metals -solids)
soda (gas, solid, liquid)
Solutions are homogenous mixtures that do not scatter light. These mixtures are created when something is completely dissolved in pure water. Therefore, they are easily separated by distillation or evaporation. Appear in one phase of matter
Examples: sugar water, salt water
PARTS OF A SOLUTION
Solvent- part that does the dissolving- water is our universal solvent
Solute- part that was dissolved (salt)
Heterogeneous mixtures are composed of large pieces that are easily separated by physical means (ie. density, polarity, metallic properties, size).
Pond Water, Vegetable Soup- Suspensions Visible particles
Starch Water: invisible to the eye :colloid
PHYSICAL PROPERTIES – OBSERVABLE TRAITS OF A MATERIAL THAT MAY BE MEASURED WITHOUT ALTERING THE SUBSTANCE
EXAMPLES: MASS, COLOR, MELTING POINT, BOILING POINT, DENSITY
WE CAN USE PHYSICAL PROPERTIES TO SEPARATE MIXTURES:
Please determine a method to separate the following and determine the type of matter:
Oil and Water
Iron and Sand
Sand and Salt
Sulfur and Sugar
WHAT ARE THE PHYSICAL PROPERTIES OF THE SUBSTANCE TO THE RIGHT?
What do you think the material is that made this bracelet?
How could you be sure?
Density- the amount of material in a given volume- unique to the material
CHEMICAL CHANGE- AN IRREVERSIBLE CHANGE THAT CHANGES THE IDENTITY AND MAKE UP OF THE MATERIALEXAMPLES:RUSTINGBURNING
There is no observable change in the quantity of matter during a chemical reaction or a physical change.
In other words, matter cannot be created nor destroyed. It is just converted from one form to another
Energy comes in two forms :
Kinetic Energy: Movement
Potential Energy: Stored
All matter, regardless of state, undergoes physical and chemical changes. These changes can be
microscopic or macroscopic.
A physical change occurs when the substance changes state but does not change its chemical composition. It is not permanent and is reversible! Example Phase Changes!
PHYSICAL CHANGE
For example: Ice melting to water. The form or appearance has changed, but the properties of that substance are the same (i.e. it has the same melting point, boiling point, chemical composition, etc.)
PHYSICAL PROPERTIES Characteristic of a substance that can be observed without changing
substance into another substance Color
Odor
Taste
Size
Physical state (liquid, gas, or solid)
Boiling point
Melting point
Density
NAMES OF WATER PHASE CHANGES
Endothermic Requires Energy to go forward
Melting: Solid Liq
Boiling (forced)
Liquid Gas
Evaporation ( spon)
Liquid Gas
Sublimation
Solid Gas
Exothermic Gives energy off
Condensation
Gas Liq
Freezing:
Liq Solid
Deposition:
Gas Solid
A substance changes into something new. It is irreversible.
ALL CHEMICAL CHANGES CAN BE WRITTEN AS A REACTION
A + B AB
A, B are the starting materials- reactants
AB is the result- product
Reaction with acids
Reaction with bases (alkalis)
Reaction with oxygen (combustion)
Ability to act as oxidizing agent
Ability to act as reducing agent
Reaction with other elements
Decomposition into simpler substances
Corrosion
Physical and chemical properties may be intensive or extensive.
Intensive properties such as density, color, and boiling point do not depend on the size of the sample of matter and can be used to identify substances.
Extensive properties such as mass and volume do depend on the quantity of the sample.
Physical properties are those that we can determine without changing the identity of the substance we are studying.
The physical properties of sodium metal can be observed or measured. It is a soft, lustrous, silver-colored metal with a relatively low melting point and low density.
Hardness, color, melting point and density are all physical properties.
SPECIFIC HEATPhysical Property that is
unique to the material
Amount of energy required to heat 1 gram of a substance by 1 degree Celsius
-Why do you choose to sit on the wooden bleachers on a cold fall day for a football game instead of the metal bleachers?
Chemical properties describe the way a substance can change or react to form other substances.
These properties, then, must be determined using a process that changes the identity of the substance of interest.
One of the chemical properties of alkali metals such as sodium and potassium is that they react with water. To determine this, we would have to combine an alkali metal with water and observe what happens.
In other words, we have to define chemical properties of a substance by the chemical changes it undergoes.
.States of Matter
The physical forms of matter, either solid, liquid, or gas, are called the states of matter.
• Solids are a form of matter that have their own definite shape and volume.
• Liquids are a form of matter that have a definite volume but take the shape of the container.
.
States of Matter (cont.)
• Gases have no definite shape or volume. They expand to fill their container.
• Vapor refers to the gaseous state of a substance that is a solid or liquid at room temperature.
RESOURCES MENU
Chemistry Online
Study Guide
Chapter Assessment
Standardized Test Practice
Image Bank
Concepts in Motion
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