CH. 3 Matter- Properties and Changes
Dec 24, 2015
TEKS
• (4) Science concepts. The student knows the characteristics of matter and can analyze the relationships between chemical and physical changes and properties.
• The student is expected to: • (A) differentiate between physical and chemical
changes and properties; • (B) identify extensive and intensive properties;
3.1 Properties of Matter• Substance - composition is uniform, does
not change between samples and is “pure”.
• Pure substances:1. Elements – Na, H, He
2. Compounds – NaCl (salt) H2O (water)
Elements and Compounds• Element- Pure substance that
can not be separated into simpler substances by physical or chemical means
• Examples: Copper, Oxygen, Iodine
Compounds• Compound- a pure substance
that is a combination of two or more elements that are combined chemically.
3.2 Changes in MatterTEKS
• (8) Science concepts. The student can quantify the changes that occur during chemical reactions. The student is expected to:
• E. Determine mass relationships between reactants and products
3.2 Changes in Matter
• Physical Change- changes which alter a substance without changing the composition.
• (Does not change the identity of the substance)–Ex: ice to water
Examples of Physical Changes
• Change in Size or Shape such as:Bend, break, cut, grind, crumple, split, or crush
• Change in State such as:Melting, freezing, vaporization, boiling, condensation, or sublimation
• Chemical Change- involves one or more substances changing into another substance
• (also called a Chemical Reaction)Ex: steel to rust
Examples of Chemical Changes
• Fermentation, • rusting, • explode, • oxidize, • corrode, • tarnish, • burn, • or rot.
• Chemical Property- the ability of a substance to combine with or change into one or more substances
• Na + Cl = NaCl (Salt)
Examples of Chemical Properties
– Ability to rust– Formation of precipitate– Reacts with water, oxygen,
acids, bases, or other substances– Flammability
Physical Properties of Matter
• Physical property- characteristic that can be observed or measured without changing the sample’s composition
• Qualitative!!
Examples of Physical Properties
–Density–Color–Odor–Taste–Hardness–Melting Point–Boiling Point
Extensive Properties–Dependent upon amount of
substance present–Mass, Length, Volume–It changes if you take away
some of the substance.
Intensive propertiesIndependent of amount of
substance presentExamples: Density, color, odor,
boiling point.Intensive properties Don’t change
and can be used to identify the substance.
Miners often got Pyrite (fool’s gold) and real gold mixed up. But Density could be used to correct the error.
The density of gold is 19.3 g/mL and the density of pyrite is 5 g/mL
Pyrite – fools gold Gold
Properties of CopperPhysical Properties Chemical Properties
Reddish brown, shiny Forms green copper carbonate compound
Malleable, ductile Forms new substances with nitric acid and sulfuric acid.
Good conductor Forms a deep blue solution with ammonia.
Density = 8.92 g/mL
Melting pt = 1085 oC
Boiling pt = 2570 oCSo changing States of Matter are PHYSICAL properties!!
Both are copper
Properties of Matter
Chemical Properties
Reactions in the presence of
Water, Air, Acid, Base
What happens when heated
Physical Properties
Intensive PropertiesDo NOT depend on the
amount________________
E.G Color, Taste, Melting/Boiling Point, Luster, Hardness
Extensive Properties Depends on the
amount_______________Mass, Volume, Length, Shape
http://www.roomd113.com/TAKS%20PP/matterclass_pres.ppt
Evidence of a Chemical Reaction
• The observation that the product has different properties than the reactant(s).
• Clues:• If something can burn• Production of energy, such as light, heat, or sound• Formation of a gas • Formation of a solid – called a precipitate • Change in odor• Change in color
Chemical Reactions• The new substances formed in the
reaction have different compositions and different properties from the substances present before the reaction occurred.
• Reactant – starting material in a reaction
• Product – ending material in a reaction
Reactant(s) turn into Product(s)• Na + Cl = NaCl (Salt)
• C. Conservation of Mass – By carefully measuring the mass before and after many chemical reactions, it was observed that the total mass involved in the reaction stayed the same.
• Law of Conservation of Mass- states that matter is neither created nor destroyed during a reaction– it is conserved
Total mass of the reactants must equal the total mass of the products.
Massreactants = Massproducts
4. According to the law of conservation of mass, how much zinc was present in the zinc carbonate?
A 40 g B 88 gC 104 D 256 g
• Antoine Lavoisier used an analytical balance to help prove this law.
Conservation of Mass problems
• Ex: 23 g of Na reacts with 35 g of Cl, what is the mass of the product, sodium chloride?
• 23 g Na+ 35 g Cl = ______ g NaCl
Ex: #2• 10 g HgO = 9.26 g Hg + _____ g of O
Properties of Matter
Chemical Properties
Physical Properties
Intensive properties
Extensive properties
MATTER
Can it be physically separated?
Homogeneous Mixture
Heterogeneous Mixture Compound Element
MIXTURE PURE SUBSTANCE
yes no
Can it be chemically decomposed?
noyesIs the composition uniform?
noyes
Colloids
SuspensionsSolutions
3.3 Mixtures of Matter
TEKS• 2.(E) plan and implement investigative
procedures, including asking questions, formulating testable hypotheses, and selecting equipment and technology
• 4. (D) Classify matter as pure substances or mixtures through investigation of their properties.
3.3 Mixtures of Matter
• Mixture- combination of two or more pure substances in which each retains its individual chemical properties.
Examples of Mixtures
–Sand and water
–Salt and Water
–If the substances do not react and can be separated by physical means, it is a mixture.
Types of Mixtures
• Heterogeneous Mixture- does not blend smoothly and individual substances remain distinct. (can see the different parts)
• Ex: salad, pizza
• Homogeneous Mixture- constant composition throughout (looks the same throughout)–Also known as solutions–Ex: Koolaid, air, sea water, sodas,
vinegar, steel
Suspension
• A heterogeneous mixture whose particles settle out over time and can be separated from the mixture by filtration
• Example lead paint
Types of Solution SystemsSYSTEM EXAMPLE
Gas-Gas Air is primarily an example of nitrogen, oxygen and argon gases.
Gas- Liquid Carbonated beverages contain carbon dioxide gas in solution.
Liquid- Gas Moist air contains water droplets in air.
Liquid- Liquid Vinegar contains acetic acid in water.
Solid- Liquid Sweetened powder drink contains sugar and other solid ingredients in water.
Solid- Solid Steel is an alloy of iron containing carbon.
Separating Mixtures
• Because mixtures are physically combined,
the processes are used to separate them arebased on the difference in physical properties of the substances.• 4 methods for separation
Distillation• Based on differences in
boiling points of the substances
• Heat mixture until substance with lowest boiling point boils to a vapor which is then condensed into a liquid
Crystallization• Results in formation of
pure solid particles of a substance from a solution containing the dissolved substance
Chromatography• Separates the components
of a mixture (called the mobile phase) on the basis of the tendency of each to travel or be drawn across the surface of another material (called the stationary phase)
3.4 Elements and Compounds
TEKS• 4. (D) Classify matter as pure substances or
mixtures through investigation of their properties.
3.4 Elements and Compounds• Element- Pure substance that
can not be separated into simpler substances by physical or chemical means
• Examples: Copper, Oxygen, Iodine
• Each element has a unique chemical name and symbol.
• The first letter is always capitalized, the rest are lowercase.–Ex:
•Oxygen O•Carbon C• Iron Fe
Periodic Table
• In 1869 Dmitri Mendeleev devised a chart which organized all of the known elements into rows and columns based on their similarities and masses.
• Can be broken down into simpler substances by chemical means (ex: using heat or energy)
Compounds• Compound- a pure substance
that is a combination of two or more elements that are combined chemically.
Common Compounds• There are 10 MILLION known compounds!• Ex: Water, Sodium chloride (salt), sucrose
(sugar), aspirin, etc.• Chemical compounds are represented by
formulas.Ex: Water is H2O
Sodium chloride is NaClSucrose is C12H22O11
Monday
• States of Matter• http://www.youtube.com/watch?v=V9WYweB
A6vA&feature=related• Oobleck• http://www.youtube.com/watch?
v=V9WYweBA6vA&feature=related
• Ex: Hydrogen and Oxygen are tasteless, odorless gases. They make water which is a clear liquid
Hydrogen + Oxygen Water
– Ex: Chlorine is a poisonous green gas. Sodium is an explosive metal. They make sodium chloride which is a white crystal that tastes salty.
– Stop pg 74
States of Matter• Solid- definite shape and volume. • Particles vibrate in place.• Particles are tightly packed.• This make a solid incompressible – can’t be
pressed into a smaller volume.
• Liquid- form of matter that flows, has constant volume, and takes the shape of its container.
Liquids
• Particles can move past each other
• Particles are close together.
• virtually incompressible
• Gas- form of matter that flows to conform to the shape of its container and fills the entire volume of its container.
Gases
• Particles of gases move freely.• Particles are very far apart. • Easily compressed.• Is normally in the gaseous state at
room temperature.
Movement of particles
Microscopic view of a gas.
Microscopic view of a liquid.
Microscopic view of a solid.
Characteristics of Gases, Liquids and Solids and the Microscopic Explanation for their Behavior
Gas Liquid Solidflows easily particles can move past one another
flows easily particles can move/slide past one another
does not flow easily rigid - locked into place particles cannot move/slide past one another
compressible lots of free space between particles
not easily compressible
little free space between particles
not easily compressible little free space between particles
assumes the shape and volume of its container
assumes the shape of its container, but volume is constant
retains a fixed volume and shape
• Vapor – refers to the gaseous state of a substance that is usually a solid or liquid at room temperature.