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Physical & Chemical Properties & Changes

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Presentation on theme: "Physical & Chemical Properties & Changes"— Presentation transcript:

1 Physical & Chemical Properties & Changes

2 Matter Anything that has mass and takes up space
Mass – a measurement that reflects the amount of matter Weight – a measure of the amount of matter and the effect of Earth;s gravitational pull on that matter. Air is matter!

3 States of Matter Solid – matter with its own definite shape and volume
Ex: wood, iron, paper, sugar Liquid – matter that flows Ex: water, blood, mercury Gas – matter that flows to conform to the shape of its container and fills the entire volume Neon, methane, air

4 States of Matter State Shape Volume Compressible? Solid Liquid Gas
Definite No Liquid Indefinite Gas Yes

5 Physical Properties A characteristic that can be observed or measured without changing the samples composition. Density Color Odor Taste Hardness Melting point Boiling point Solubility

6 Extensive Properties Intensive Properties
Depends of how much (the extent) matter there is Ex: mass, length, volume Intensive Properties Independent (does NOT depend) of how much matter Substance can often be identified by intensive property Ex: density, temperature Pour two quantities of same-temperature water together and take temp. again. No change. Put a cork in a small beaker of water. It floats. Repeat with a large beaker of water. It still floats.

7 Chemical Properties The ability of a substance to combine with or change into one or more other substances Combustibility Sodium reacts with water, may combust Reactivity with other substances Iron rusts when exposed to oxygen

8 Types of Matter Substance (Pure Substance) Element Compound Mixture
Matter that has uniform and unchanging composition Only 1 type of matter present Element A pure substance that cannot be separated into simpler substances by physical or chemical means Compound Combination of two or more different elements chemically combined Mixture Combination of two or more pure substances in which each pure substances retains its chemical properties

9 Classes of Matter Matter Pure substance mixture element homogeneous
compound heterogeneous Pure substances- on periodic table Compounds- water, salt, sugar, carbon dioxide Solutions- salt water, air, brass

10 Mixtures Homogeneous Mixture- Heterogeneous Mixture-
Has a constant composition throughout Single phase Looks the same throughout Also referred to as solutions Heterogeneous Mixture- Does not blend smoothly throughout Individual substances remain distinct

11 Examples Element Compound Heterogenous Mix. Homogenous Mix. Carbon
Iron Gold Mercury Compound Water Carbon Dioxide Table Salt Aspirin Heterogenous Mix. Concrete Milk Wood Sand Homogenous Mix. Air Salt water White gold Brass Brass is a mixture of copper and zinc Mixture- contains more than 1 substance. Can be separated into pure components. Homogeneous- uniform in composition (solutions) i.e. salt water, air Heterogeneous- not uniform throughout i.e. clay in water, soup, concrete Separation methods- filtration, evaporation, centrifuge (blood), magnets

12 General Classes of Elements
Metals – Have luster (shine) Malleable (not brittle) Ductile (can be drawn into wires) Conduct heat and electricity Nonmetals – Brittle Poor conductors of heat and electricity Metalloids – Have characteristics of both metals and nonmetals

13 Solutions A homogeneous mixture Composed of 2 parts
Solvent – substance there is more of Dissolving substance Solute – substance that is added to solvent Dissolved substance Concentrated solutions have a lot of solute in the solvent.



16 Physical Changes Alter a substance without changing its composition
Identifying properties remain unchanged Phase change Breaking or cutting Dissolving Bend Crumple Split Crush distillation

17 Chemical Changes One or more substances changing into new substances
Different substances formed Burning Rusting Decaying or spoiling Fermentation Acid reacting with metal

18 Signs of a Chemical Change
Heat gained or lost Production of a gas Formation of a precipitate Color change Sulfuric acid and sugar- heat, gas, and color change.


20 Water breaking down into hydrogen and oxygen gases
Ice changing to liquid water Physical change Chemical change

21 Law of Conservation of Mass
Mass is neither created nor destroyed during a chemical reaction, it is always conserved. Mass of reactants always equals mass of reactants. Massreactants = Massproducts

22 Law of Definite Proportions
Regardless of amount, a compound is always composed of the same elements in the same proportion by mass. Water, H2O Always made of 2:H’s and 1:O no matter how much water you have

23 Percent by Mass % by mass = Mass of Element X 100 Mass of Comound

24 Law of Multiple Proportions
When different compounds are formed by a combination of the same elements, different masses of one element combine with the same relative mass of the other element in a ratio of small whole numbers. H2O vs. H2O2 Water has 2 H’s for every 1 O Hydrogen peroxide has 2 H’s for every 2 O’s

25 Methods of Separating Mixtures
Use different properties of substances to separate them Sand and iron filings Sand and salt Sand and water Water and salt water Oil in water (immiscible liquids) Mixture of pigments Remove iron with magnet Dissolve salt, evaporate water filter Distill the water Settle and extract less dense liquid Paper chromatography

26 Chromatography Distillation

27 Chemical Symbols First letter is ALWAYS capitalized
Second letter, if there is one, is NEVER capitalized Co and CO are very different! Some elements use their Latin name 2 O means 2 oxygen atoms O2 means 2 oxygen atoms are chemically bonded together

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