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CHEMISTRY I

CHEMISTRY I. Unit 1 The Science of Chemistry and Matter. Elements. Energy. What is Chemistry ? POD: Discuss with the person next to you different ways you think chemistry is present in your everyday life and write it down on your pod. Laboratory. Compounds. Classification of matter.

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CHEMISTRY I

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  1. CHEMISTRY I Unit 1 The Science of Chemistry and Matter

  2. Elements Energy • What is Chemistry? • POD: Discuss with the person next to you different ways you think chemistry is present in your everyday life and write it down on your pod. Laboratory Compounds

  3. Classification of matter Objectives: • Relate chemistry to everyday life. • Identify traditional areas of study in chemistry. • Define matter. • Categorize samples of matter as a mixture or a substance. • Distinguish between homogeneous and heterogeneous mixtures. • Describe ways components of a mixture can be separated • Explain the difference between a compound and an element.

  4. Chemistry is the study of the composition of matter and the changes matter undergoes. • Matter: anything that has mass and occupies space. • There are five traditional areas of study for chemistry • Organic chemistry: study of chemicals containing carbon. • Inorganic chemistry: study of chemicals that do not contain carbon. • Biochemistry: study of processes that take place in organisms. • Analytical chemistry: focuses on composition of matter • Physical chemistry: describes behaviors of chemistry.

  5. Chemistry far and wide: • Materials: plastic, glass, ceramics, perfumes, food, etc. • Energy: fossil fuels, food, solar batteries, nuclear • Medicine: penicillin, aspirin, Vitamin C • Agriculture: fertilizer, pesticides, growth hormones • Environment: ozone, carbon dioxide- global warming, pollution • Astronomy: composition of planets and stars

  6. Classification of matter • Mixtures: a physical blend of two or more components. Ex. Salad, pizza, milkshake and air • Heterogeneous mixtures: the composition is not uniform

  7. Homogeneous mixtures: composition is uniform throughout. Also called solutions. • In a solution we have a solute (substance being dissolved) and a solvent (substance dissolving solute) • Water is the universal solvent • Most are liquids • Some are solids. Example alloys of different metals like brass, an alloy of copper and zinc. • For tomorrow research what other types of alloys we use. • Some are gases like the air

  8. Figure 1.4a MIXTURES HETROGENOUS HOMOGENOUS

  9. Different Physical Property Technique Boiling Point Distillation State of Matter (solid/liquid/gas) Filtration Adherence to a Surface Chromatography Volatility Evaporation Density Centrifugation & Decanting 0 Separation of mixtures • Separate mixtures based on different physical properties of the components

  10. Distillation Filtration 0

  11. Pure Substances: have fixed composition. • Elements are the simplest form of matter that has its unique set of properties. • Ex. Gold is an element. All atoms of gold have the same properties. • Elements are shown in the Periodic Table. • There are more than 100 elements, most of them occur naturally. • Elements are represented by one (a capital letter) or two letter symbols(a capital letter and a lowercase letter). • Ex. C: carbon Co: cobalt

  12. Compounds is a substance that contains two or more elements chemically combined in a fixed proportion. • Represented by chemical formulas using symbols of elements present in compound and subscripts indicated how many atoms of each element is present. • Ex. H2O: water CO: carbon monoxide CO2: carbon dioxide

  13. Figure 1.7b

  14. Learning Check: • How do elements relate to compounds? • How do elements and compounds relate to mixtures? • What is the main difference between pure substances and mixtures?

  15. Learning Check: • How do elements relate to compounds? Compounds are made from elements chemically combined. • How do elements and compounds relate to mixtures? Elements and compounds physically combine to form a mixture. 3. What is the main difference between pure substances and mixtures? Pure substances have a fixed composition and the composition of mixtures may vary.

  16. Classwork: p53 #1-3 HW: Bring tomorrow any sample of matter and share with the class how you would classify the sample and why. (Don’t use water as an example, too easy!!)

  17. Changes in matter • Identify properties as extensive or intensive. • Define a physical property and a chemical property. • Describe a physical change. • Describe what happens during a chemical change. • Identify clues that a chemical change has taken place.

  18. Changes in matter • Physical change : same substance remains after change. • Ex. Pounding, cutting, dissolving • Changes of state: melting, boiling, condensing, etc.

  19. Chemical change: a new substance (different characteristics) appears after the change. (a chemical reaction) • Evidence of chemical change • Production of gas (observed as bubbles or change of odor) • Release or absorption of energy (change in temperature or giving off light) • A color change • Formation of a precipitate (solid formed when two clear solutions combine and become cloudy) • Ex. Burning, digestion, fermentation • During a chemical reaction, mass of products is equal to mass of reactants: law of conservation of mass.

  20. Physical property: quality of a substance that can be observed or measured without changing the substance’s composition. Ex. Length, color, temperature • Extensive: depend on amount of matter present. Ex. Mass, length, volume • Intensive: do not depend on amount of matter present. Ex. Density, color, malleability (can be hammered), ductility (can be turned into wires), conductivity, melting point.

  21. Chemical property : describes the behavior of a substance undergoing a chemical change. Describes how it reacts with other materials like air, water, and acids. • Characteristics could be: acidity, flammability, reactivity, oxidizing ability, explosiveness. • Indicating it does not react is also a chemical property.

  22. Energy and change • Energy is the capacity to do work. Always involved when there is a change in matter. • Endothermic and exothermic processes • Endothermic: energy is absorbed from the surroundings. (Ex. Boiling water) YouTube - "Cool" Reaction: Ammonium Thiocyanate and Barium Hydroxide Octahydrate • Exothermic: energy is released to the surroundings. (Ex. fire) YouTube - Exothermic reaction Potassium Permanganate

  23. Learning check: • Classify the following as a chemical or physical property • Is red • Reacts with water • Boils at 88C • Dissolves in gasoline • Is corrosive • Classify the following as a chemical or physical change • Alcohol evaporating • An explosion • Digesting food • Salt dissolving in water • Grass growing

  24. Learning check: • Classify the following as a chemical or physical property • Is red physical • Reacts with water chemical • Boils at 88C physical • Dissolves in gasoline physical • Is corrosive chemical • Classify the following as a chemical or physical change • Alcohol evaporating physical • An explosion chemical • Digesting food chemical • Salt dissolving in water physical • Grass growing chemical

  25. Classwork: pg 62 #6-8

  26. CHEMISTRY I Unit 1 The Science of Chemistry and Matter

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