Post on 14-Jan-2016
MatterPSc.2.1: Understand types, properties, and structure of matter.
What is matter?
Anything that has mass and volume (takes up space)
Examples: wood, candy, water, ice
Forms of energy such as electricity, heat, and lightning are NOT matter according to the definition.
Classifying Matter
Matter
Pure substance
Element
compound
Mixture
heterogeneous
homogeneous
Pure Substance
Has a fixed chemical compositionExamples: water (H2O) Hydrogen (H2)
The composition of a pure substance is the same all of the time. Sugar is a pure substance because its chemical composition is the same no matter what manufacturer produces it.
Pure Substances Can Be Classified as either element or compound. Element: composed of only 1 kind of
atom. You will find elements listed on the Periodic Table of Elements;
Elements have a single symbol that is either one or two letters.
If the symbol is two letters, the first one is ALWAYS capitalized and the second is ALWAYS lower case.
Example: carbon (C), Helium (He)
Elements can be classified as metals, non-metals or metalloids (semi-metals)The periodic table of elements
organizes the elements into metals, non-metals and metalloids.
Metals
Metalloids
Non-metal
s
Compound
a substance formed from two or more different elements that have undergone a chemical reaction to combine them
Has a chemical formula that contains the symbols of each element in the compound
Example: oxygen (element) combines with hydrogen (element) to create a water molecule (H2O)
Mixtures
Have a composition that varies depending upon the amount of substances combined or mixed together
Example: sugar mixed with tea; ice cream sundae; soil
Mixtures can be classified according to how well the substances are mixed. Heterogeneous mixture: substances
do not mix well; you can see different layers or substances settle out to bottom
Homogeneous mixture: substances are well mixed and look like one substance; you don’t see layers or particles settling to the bottom
Homogeneous and heterogeneous mixtures can be classified as……
Solutions: homogeneous mixture where particles are evenly dispersed throughout
Suspension: heterogeneous mixture where particles are somewhat evenly dispersed
Colloid: heterogeneous mixture of tiny particles that are intermediate in size suspended in a liquid, solid or gas; will scatter light (tyndall effect)
Classify the following……
Orange juice with pulpLithium (Li)Carbon monoxide (CO)KoolaidChocolate chip cookiesSugar water
Solutions (homogeneous) Solutions are homogeneous mixtures of substances.
When a substance dissolves in another substance it is described as soluble because there is an attraction between the particles of the solute (substance being dissolved) and the solvent (the substance doing the dissolving.
Insoluble: the substance will not dissolve in the solvent because there is a lack of attraction between the particles.
Solutions can be described in the following manner:
Unsaturated: there is more solvent and less solute so there is “room” for more solute to dissolve
Saturated: the solvent has dissolved the maximum amount of solute: “no more room”
Supersaturated: there is more solute than the solvent can dissolve and the excess settles out
Temperature is very important in the process of dissolving. Usually at high temperatures, more solute can dissolve. The EXCEPTION is gases. More gas particles can dissolve if the temperature is low.
States (Phases) of Matter
Kinetic Molecular Theory
All matter is composed of tiny, constantly moving particles.
The kinetic energy of these particles increases with more motion.
As kinetic energy (and motion) of particles increases, the temperature of the matter increases.
Solids
Have a definite shape
Have a definite volume
Have low Kinetic energy because the particles are packed so close together that they vibrate but don’t move around
Crystalline solids: particles are arranged in a repeating geometric pattern
Diamonds, sugar, salt
Amorphous solids: particles do not have a defined pattern
Wax, glass
Liquids
Have a definite volume
Measure using a graduated cylinder
DO NOT have a definite shape
Take the shape of the container that its in
Have more Kinetic energy than liquids because particles are not as closely spaced; the particles can move past each other but are still close
Gases
DO NOT have a definite shape
DO NOT have a definite volume
Have very high Kinetic energy
Particles are tiny and spread very far apart and move very fast.
Changes in State or Phase Require the addition (endothermic) or removal (exothermic) of heat or
energy
Kinetic energy is due to motion of particles. Potential energy is related to the space between particles. Change Name Process Kinetic
EnergyPotential Energy
Solid to liquid
Melting Endothermic
increases decreases
Liquid to solid
Freezing Exothermic Decreases increases
Liquid to gas (vapor) at the boiling point
Vaporization Endothermic
Increases Decreases
Gas to liquid Condensation
Exothermic Decreases Increases
Solid to gas (vapor)
Sublimation Exothermic Increases Decreases
Gas to solid deposition Endothermic
Decreases IncreasesEvaporation is also a liquid to gas change but the substance does not have to be boiling.
**melting point = freezing Point temperature
Phase Changes
Solid
Liquid
Gas
Melting Vaporization
Condensation
Freezing
Liquid
Sublimation
Melting Vaporization
Deposition
Condensation
Solid
Freezing
Gas
Water
Waterand IceIce
Water and Steam
Steam
-20
0
20
40
60
80
100
120
0 40 120 220 760 800
Heating Curve for Water
Temperature is constant during a phase change!
boiling
melting
Vaporization versus Evaporation
Vaporization: Substance must be heated to its boiling point
Takes place throughout the entire liquid
The attractive forces between molecules is very low.
Fast and vigorous process
Evaporation: Substance does not have to be at its boiling temperature
Takes place at all temperatures
Slow process
Takes place only at the surface of the liquid
Depends on external factors such as surface area, wind, humidity, and temperature
https://www.youtube.com/watch?v=7zo10Yxicn1
Properties of matter
Physical property: a characteristic that can be observed about a sample of matter without changing the identity of the matter
Magnetism, density, color, shape, weight, volume, mass, phase or state
Physical properties can be used to separate mixtures of substances
Sand and water mixture can be separated by filtering through filter paper or strainer. The sand will be trapped by the filter paper and the water will flow through.
A mixture of sand and iron can be separated using a magnet because iron is magnetic and will be attracted to the magnet. Sand is not.
A mixture of salt and water can be separated by boiling the mixture. Water evaporates and the solid salt will be left behind.
A mixture of oil and water can be separated because oil and water have different densities and the oil will float on top of the water because it is less dense.
Chemical property: characteristics of a substance that indicate how it will interact with other matter or undergo a specific chemical change
Flammability: will it ignite or burn
Reactivity: will it react with other substances
Lithium is highly reactive with water but not oil.
Helium is not flammable but oxygen is.
Physical Changes in Matter
Physical changes are changes in the form or phase of a substance but the identity is still the same Properties remain the same
Physical changes are reversible; ice can be melted and liquid water results however the chemical makeup is still the same H2O
Physical properties can be used to separate mixture
Examples: dissolving a substance in another one
grinding something into smaller pieces
cutting a piece of wood
any phase or state change: melting, boiling, freezing, sublimation, condensation, deposition
Chemical changes in Matter
Chemical changes will change one substance into a completely different Ewith new chemical and physical properties
Cannot be reversed Rusting, burning, tarnishing, decomposing, rotting, oxidizing
Can be recognized by the following signs: Gas or bubbles are produced
Odor changes
Precipitate (a solid substance) forms usually when 2 liquids are combined
Energy change occurs (heat and/light produced, temperature changes (gets hotter or colder)
Color changes: something clear turns to another color; a color disappears; a color changes to a different color