* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Chapter III: Matter - Norwell Public Schools
Gas chromatography wikipedia , lookup
Periodic table wikipedia , lookup
Photopolymer wikipedia , lookup
Organic chemistry wikipedia , lookup
Safety data sheet wikipedia , lookup
Inorganic chemistry wikipedia , lookup
Stoichiometry wikipedia , lookup
Chemical thermodynamics wikipedia , lookup
Vapor–liquid equilibrium wikipedia , lookup
Chemical element wikipedia , lookup
Abundance of the chemical elements wikipedia , lookup
Registration, Evaluation, Authorisation and Restriction of Chemicals wikipedia , lookup
Drug discovery wikipedia , lookup
IUPAC nomenclature of inorganic chemistry 2005 wikipedia , lookup
Chemistry: A Volatile History wikipedia , lookup
History of chemistry wikipedia , lookup
Gas chromatography–mass spectrometry wikipedia , lookup
Condensed matter physics wikipedia , lookup
Matter: Properties and Changes Chapter 3.1: Properties of Matter Substances • Review: • Matter is anything that has mass and takes up space. • Matter with uniform and unchanging composition is pure substance. • • ie~ Table salt (NaCl) What about H2O? Pure water = yes; seawater / tap water = no. Sates of Matter • States of Matter • All matter that exists can be classified into one of three forms: • Each can be distinguished by the way it fills a container. • Exception to rule: plasma (fourth state of matter) • Found in lightning bolts and stars. Changes States of Matter 3.1 Properties of Matter • Solid • • • States of Matter Definite shape and volume. Particles tightly packed. Expands slightly when heated. Changes States of Matter 3.1 Properties of Matter • Liquid States of Matter • Flows and has constant volume. • Particles not held in place and packed less closely. • • • Able to move past one another. Takes shape of container. Expands when heated. es es of Matter atter States of Matter • Gas • • Flows to conform to shape of container & fills entire volume. • Expands to fill containers. Particles are very far apart • Easily compressible. States of Matter • Gases vs Vapor • • Do not mean the same thing! • Vapor refers to gaseous state of substance that is solid or liquid at room temperature Gas is a substance that is naturally in the gaseous state at room temperature. • Helium? Neon? Steam? Physical Properties of Matter • Characteristic that can be observed or measured without changing the composition. • • Also describe pure substances. • Uniform and unchanging compositions = consistent and unchanging properties. Examples include: Density, color, odor, hardness, melting point, boiling point. Physical Properties of Matter • Two Types • • Extensive • Dependent on the amount of substance present. Examples include: Length, mass, & volume. Physical Properties of Matter • Two Types • • Intensive • • Independent on the amount of substance present. Examples include: Density- always the same regardless of how much substance is present. Substances can be identified by intensive properties. • ie~ scent Chemical Properties of Matter • The ability of a substance to combine with or change into one or more other substances. • Composition of substance changes. • Results from contact with other substances or addition of Chemical Properties energy (thermal or electric). • Example: Iron = Forms rust when in contact with oxygen in air • Copper = Chemical Properties of Matter • Each substance has its own unique set of physical and chemical properties. • Chemical Properties - Copper: Can be shaped into different forms (physical) or turns green when in contact with air (chemical) Matter: Properties and Changes Chapter 3.2: Changes in Matter Changes in Matter • Physical Change • Changes in appearance but not composition. • Examples include: 1) Cutting sheet of paper 2) Breaking glass object 3) Crumpling piece of aluminum foil Changes in Matter • Phase Change • Transition of matter from one state to another. • Depends on temperature and pressure of surroundings. • • As temperature and pressure change, substances change from one phase to another. Example is the water cycle: • 1) Ice (solid) is heated to become liquid water. 2) Add more heat, liquid water boils and is converted to steam (gas). • What type of changes are these? Physical (Different appearance but same composition) Changes in Matter • Phase Change • Melting and Boiling Points • The temperature and pressure at which a substance undergoes a phase change. • Intensive physical properties that can be used to identify unknown substances. Changes in Matter • Chemical Change • • One or more substances changing into new substances. • aka~ chemical reaction New substances formed have different compositions and properties. Changes in Matter • Chemical Reaction • Starting substances = reactants. • New substances formed = products. emical change - Changes in Matter • Chemical Reaction • Evidence includes a change in properties. idence of Chemical Change • ie~ spoiled food: What are some changes in properties? Look, taste, digestability... Changes in Matter • Law of Conservation of Mass • Mass is neither created nor destroyed during a chemical reaction. • • It is conserved. • mass of reactants = mass of products. Although chemical changes occur, total mass remains constant. Changes in Matter Law of Conservation of Mass • Law of Conservation of Mass - • Mass is neither created nor destroyed during a chemical reaction. A 10.0 g sample of magnesium reacts with oxygen to form 16.6 g of Magnesium oxide. How many grams of oxygen reacted? Matter: Properties and Changes Chapter 3.3: Mixtures of Matter Changes in Matter • Most everyday matter occurs as mixtures. • Combination of two or more pure substances. • Each pure substance retains its individual chemical properties. • Composition of mixtures is variable. Changes in Matter • Types of Mixtures • Heterogeneous • • • • Mixture that does not blend smoothly. Composition is not uniform. Substances remain distinct. Examples include: salad dressing, orange juice, etc. Changes in Matter • Types of Mixtures • Homogeneous • • Has constant composition throughout. • Always has single phase. Referred to as solutions. Changes in Matter • Solutions • • Most familiar with liquid forms. • Examples include: tea, lemonade, etc Solution systems can be solid, liquid, or gas. • Solid-solid solutions of metals are known as alloys. • Examples include: steel, bronze, 14-karat gold. Changes in Matter Homogeneous Mixture (solution) - • Solutions Separating Mixtures • Important to be able to separate mixtures to understand nature of matter. • Use physical processes to separate mixtures based on physical properties. • ie~ magnet to separate metal from sand. MixturesSeparatingSeparating Mixtures • Filtration • Filtration - Separates heterogeneous mixtures composed of solids and liquids. • Uses a porous barrier. Separating Mixtures • Distillation • • Used to separate most homogeneous mixtures. Distillation - Based on differences in boiling points. 1) Mixture is heated until lower boiling point boils to vapor. 2) Vapor is condensed into liquid and collected. Separating Mixtures • Crystallization • Results in the formation of pure solid particles of a Crystallization substance. • Solid particles come from solution containing dissolved substance. • • Solids are highly pure Example: rock candy Separating Mixtures • Sublimation • Sublimation Solid changes to vapor without going through liquid • Used to separate one solid that sublimates form one that does not. phase. Separating Mixtures • Chromatography • Chromatography Separates components of a liquid mixture (mobile phase) based on ability of each to travel across another material (stationary phase). • Components flow through stationary phase at different speeds. Matter: Properties and Changes Chapter 3.4: Elements and Compounds Elements & Compounds • • Matter can take many different forms. • All matter can be broken down into basic building blocks called elements. Element is a pure substance that cannot be separated into simpler substances by physical or chemical means. • • 92 natural elements Several others that have been developed Elements & Compounds • • • Elements have unique chemical names & symbols. • Names consist of 1/2/3 letters. • First ALWAYS capitalized; rest are lowercase. 92 natural elements not evenly distributed. • • H2: 75 % of mass of universe. O2, H2, C: 90% of human body Under normal conditions, elements can be found in each type of phase. (ie~ Cu, Hg, He) Elements & Compounds • Elements organized into a periodic table. • • • Based on similarities and masses Rows = periods Columns = groups / families • Elements in same group have similar chemical and physical properties. Elements & Compounds • Compounds made up of two or more different elements that are chemically combined. • • Most matter in the universe exists as compounds. • 10 million known; ~ 100,000 developed each year. Chemical formulas of compounds • Composed of chemical symbols and subscripts. • • Subscripts indicate number of elements in each compound. ie~ H2O, NaCl Elements & Compounds • Compounds can be broken down into simpler elements by chemical means. • Compounds generally more stable than individual elements. • • Requires energy (ie~ heat or electricity). Electrolysis is breakdown of H2O. *** What do you notice about the amount of H2 compared to the amount of O2? Properties of Compounds • Properties of a compound are different from those of the individual elements. • ie~ H2O • How is H2O different than H2 & O2? Properties of Compounds • Properties of a compound are different from those of the individual elements. Properties of Compounds vs. Elements Properties of Compounds • Organization of Matter • Pure substances & mixtures. • Separation??? Law of Definite Proportions • Elements in compounds combine in definite proportions by mass. • Law of Definite Proportions = Compound is composed of same elements in the same proportion by mass. • Mass of the compound = sum of masses of elements that make up the compound. Law of Definite Proportions Definite Proportions - • Law of Definite Proportions - in a compound can be Amounts of elements expressed as percent by mass. • Ratio of the mass of each element to the total mass of the compound. A 1.0 g sample of hydrogen reacts with 19.0 g of fluorine. What is the % of hydrogen in the compound? sample of hydrogen reacts with 19.0 g of fluorine. Wh of hydrogen in the compound? Law of Definite Proportions • Amounts of elements in a compound can be expressed as percent by mass. • Ratio of the mass of each element to the total mass of the compound. • Percent by mass the same regardless of amount of sucrose; each has the same mass proportion Law of Multiple Proportions • Use when comparing different compounds composed of the same elements. • Law of Multiple Proportions = 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. one element combine with the same relative mass of the other element in a ratio of small whole numbers Law of Multiple Proportions mass ratio of Compound I 1.793 g Cu / g Cl = = 2.000 mass ratio of Compound II 0.8964 g Cu / g Cl • Mass ratio of copper to chlorine in Compound 1 is exactly two times the mass ratio of copper to chlorine in Compound II. • 2:1 10