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Explore the differentiation between physical and chemical changes and properties, and classify matter as pure substances or mixtures. Learn about sure signs of a chemical change, physical changes, chemical properties, and extensive versus intensive properties. Test your knowledge with quizzes and understand mixtures, pure substances, and various separation techniques. Discover the fascinating world of matter through engaging examples and interactive activities.
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TEKS • 4 (A) differentiate between physical and chemical changes and properties; • 4 (B) identify extensive and intensive properties; • 4 (D) classify matter as pure substances or mixtures through investigation of their properties.
Physical vs. Chemical Changes • Examples: • rusting iron • dissolving in water • burning a log • melting ice • grinding spices • Chemical • Physical • Chemical • Physical • Physical
Sure Signs of a Chemical Change • Energy Change (Temperature and Light) • Gas Produced (not from boiling!) • Precipitate – a solid formed by mixing two liquids together • Color Change (Be Careful) http://jchemed.chem.wisc.edu/JCESoft/CCA/CCA0/MOVIES/S1047.MOV
Physical Changes • can be observed without changing the identity of the substance Some physical changes would be • Phase Change • boiling of a liquid • melting of a solid • dissolving a solid in a liquid to give a homogeneous mixture — a SOLUTION.
Changes Quiz Are the following changes considered chemical or physical? • 1. Sharpening a pencil • 2. Dissolving Koolaid in water • 3. Silver Tarnishing • 4. Alcohol evaporating • 5. Milk souring
Chemical Properties and Chemical Change • Burning hydrogen (H2) in oxygen (O2) gives H2O. • Chemical change or chemical reaction — transformation of one or more atoms or molecules into one or more different molecules.
Physical Properties ( see STAAR field guide) What are some physical properties? • color • melting and boiling point • odor
Graphite — layer structure of carbon atoms reflects physical properties.
Physical vs. Chemical Properties • physical • chemical • physical • physical • chemical • Examples: • melting point • flammable • density • magnetic • tarnishes in air
Physical Chemical Properties quiz Chemical Physical Physical Physical Physical Chemical Physical Chemical • Combustible • Hard • 13 Kilograms • Boils at 200°C • Density of 6.1g/cm³ • Corrodes in air • Soluble in water • Volatile in water
What are Extensive and Intensive Properties? All Physical Properties of Matter can be classified as Extensive or Intensive. • Extensive Properties- depend on the amount of matter Ex) Mass • Intensive Properties- DOES NOT depend on the amount of matter. Ex) luster, density (Mass/Volume ratio) Determine Extensive or Intensive from the Physical properties on slide 9.
Intensive/Extensive Properties Quiz • Hard • 13 Kilograms • Boils at 200°C • Density of 6.1g/cm³ • Corrodes in air • Soluble in water
Mixtures and Pure Substances• Matter can be classified as a mixture or a pure substance.
Mixtures • A mixture has variable composition • • A homogeneous mixture has the same properties throughout. • A heterogeneous mixture has different properties in different parts of the mixture.
Separation of Mixtures filtration distillation
Separation of Mixtures Chromatography- involves passing a mixture dissolved in a "mobile phase" through a stationary phase. Chromatography works on the principle that different compounds will have different solubilities and adsorption to the two phases, which will allow for their separation. Decantation- is a process of carefully pouring a solution from a container in order to leave the precipitate (sediments) in the bottom of the original container.
Pure Substances A pure substance always has the same composition. • Pure substances are of two types: Elements which cannot be broken down chemically into simpler substances Compounds which can be chemically broken down into elements Water is a compound. All the components are the same—H2O molecules.
MATTER yes no Can it be physically separated? MIXTURE PURE SUBSTANCE yes no yes no Is the composition uniform? Can it be chemically decomposed? Homogeneous Mixture (solution) Heterogeneous Mixture Compound Element How can it be separated ? How can it be separated ? Filtration Distillation Chromatography Chemically Electrolysis Nuclear Reaction Matter Flowchart
Types of Mixtures • Variable combination of 2 or more pure substances. Heterogeneous –visibly separate phases Homogeneous – Same throughout