340 likes | 749 Views
Matter and Change. Unit 2. Chemistry is the study of matter and the changes that take place with that matter. Matter is anything that has mass and volume . Examples of Matter. States of Matter (Review). separation. separation. compound. element. chemical. matter. solution. physical.
E N D
Matter and Change Unit 2 Chemistry is the study of matter and the changes that take place with that matter. Matter is anything that has mass and volume.
separation separation compound element chemical matter solution physical heterogeneous mixture pure substance mixture
Element, compound, or mixture? Mixture Element Element Compound Mixture Compound
Vocabulary Based on the picture below, how would you define homogeneous and heterogeneous? Homogenous: Heterogeneous: Uniform in appearance and composition; A mixture of 2 or more pure substances that are evenly mixed throughout VARIED in composition and appearance; A mixture of 2 or more pure substances in an unfixed ratio
Definite vs. Variable Composition Compound Mixture Variable Definite What's the ratio of Red : Blue?
Vocabulary: Mixture A combination of 2 or more substances that are not chemically combined and have variable composition Pure Substance (H2O) Mixture!
Vocabulary: Solution A homogeneous mixture composed of one phase of matter
Vocabulary Pure Substance: a chemical substance with a fixed composition element compound
Pure Substances Element: has only one type of atom Compound: a combination of 2 or more elements chemically combined.
Summary of Mixtures • Can appear homogeneous OR heterogeneous • Has 2 types of pure substances present • Can be separated physically (ex: magnetic force, evaporation, filtration) • Has variable composition
No bonds break Physical Separation (of a mixture) Mixture No new substance
Chromatography This technique separates substances on the basis of differences in solubility in a solvent.
Filtration In filtration solid substances are separated from liquids and solutions.
Distillation Distillation uses differences in the boiling points of substances to separate a homogeneous mixture (solution) into its components.
Break bonds Chem reaction Chemical Separation (of a compound) Compound Elements New substances!
Elements • Can appear homogenous • Is considered a pure substance • Has only one type of atom • Cannot be broken down into a simpler substance • Has a fixed/definite composition http://vimeo.com/6929507
Compounds Compounds can be broken down into more elemental particles.
Compounds • Can appear homogeneous • Is considered a pure substance • Always has only one type of molecule • Can only be separated by a chemical reaction • Has a fixed/definite composition
Both: Elements & Compounds • Can appear homogeneous • Are a pure substance • Has fixed or definite composition
REVIEW! • Explain how elements and compounds are the same. • Explain how elements and compounds are different. Compounds can be broken down into 2 or more elements Pure substances! Appears homogeneous! Fixed/definite composition!
The set of characteristics used to identify a substance are the properties used… PHYSICAL • A quality that can be observed where no changes to the substance are required (ID unchanged) CHEMICAL • Any quality that can ONLY be established by changing the chemical ID of the substance
Physical Properties Physical properties describe characteristics like • Color • Hardness • Density • Texture • Phase • Boiling Point • Odor • Polarity • Solubility • Concentration • Ductility • Malleability • Elasticity • Viscosity • Mass • Volume • Conductivity
Chemical Properties • pH • Reactivity with water or other compounds • Toxicity • Radioactivity • Flammability • Oxidation
Intensive v. Extensive Properties • Intensive Properties… • Depend on the type of matter, NOT the amount of matter in a sample. • Extensive Properties… • Depend upon the amount of matter in a sample. • Ex: Density, BP, MP, FP color, odor, etc. • Ex: Mass, volume, energy, etc.
Physical Changes Can be a change in PHASE as a result of heating, cooling, or pressure. Also covers changes in the size of the substance WITHOUT CHANGING THE CHEMICAL IDENTITY
Chemical Changes • The process of forming a new substance OR the altering of the previous substance(s) chemical identity. • As wood burns, CO2 gas and H2O vapor are released. • New materials are formed by the rearrangement of molecules
Physical vs Chemical Changes • IS A NEW SUBSTANCE FORMED? • If no …. Physical change • If yes … Chemical change • Signs of a chemical change: • Color/odor change • Produce a gas / (not boiling) • Change in temperature • 4) Change in properties • 5) Precipitation of a solid from • 2 liquids Physical changes can do some of these too!
Some Practice • Grape juice fermented into wine • Wood to ashes • Fuel burning • Rocks crushed into powder • Water boiling • Condensation of water C C C P P P