Solid, Liquid and Gas Classification of Matter Separation Techniques Chapter 3 Solid, Liquid and Gas Classification of Matter Separation Techniques

Solid, Liquid, Gas (a) Particles in solid (b) Particles in liquid (c) Particles in gas

Solid H2O(s) Ice Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 31

Liquid In a liquid H2O(l) Water molecules are in constant motion there are appreciable intermolecular forces molecules are close together Liquids are almost incompressible Liquids do not fill the container some writing from Kotz (PowerPoints online) H2O(l) Water Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 31

Gas H2O(g) Steam Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 31

Gas, Liquid, and Solid Gas Liquid Solid Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 441

Some Properties of Solids, Liquids, and Gases Property Solid Liquid Gas Shape Has definite shape Takes the shape of Takes the shape the container of its container Volume Has a definite volume Has a definite volume Fills the volume of the container Arrangement of Fixed, very close Random, close Random, far apart Particles (compressible) Interactions between Very strong Strong Essentially none particles

MATTER yes no MIXTURE PURE SUBSTANCE yes no yes no Homogeneous Mixture Can it be physically separated? MIXTURE PURE SUBSTANCE yes Is the composition uniform? no yes Can it be chemically decomposed? no Homogeneous Mixture (solution) Heterogeneous Mixture Compound Element Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

Pure Substances Element composed of identical atoms EX: copper wire, aluminum foil Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

Pure Substances Compound composed of 2 or more elements in a fixed ratio properties differ from those of individual elements EX: table salt (NaCl) Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

Mixtures Variable combination of 2 or more pure substances. Heterogeneous Homogeneous Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

Pure Substances Law of Definite Composition A given compound always contains the same, fixed ratio of elements. Law of Multiple Proportions Elements can combine in different ratios to form different compounds. Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

Two different compounds, each has a definite composition. Pure Substances For example… Carbon, C Oxygen, O Carbon monoxide, CO Carbon, C Oxygen, O Oxygen, O Carbon dioxide, CO2 Two different compounds, each has a definite composition. Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

Mixtures Solution homogeneous very small particles Tyndall Effect Solution homogeneous very small particles particles don’t settle EX: rubbing alcohol Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

Air is a Solution Air Nitrogen Helium Oxygen Neon Water vapor Carbon dioxide Argon Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 34

An alloy is a mixture of metals. Brass = Copper + Zinc Solid brass homogeneous mixture Solid Brass Consumer Tip Pay attention to labels when purchasing brass. Brass is sold with the label ‘Brass’ or ‘Solid Brass’. ‘Brass’ means brass coated – the object is not ‘solid brass’. It is likely inexpensive, cheap zinc in the center and has only a thin coating of brass on the outside. Toilet bowl seat screws are often sold as ‘brass’ ($1.29) or ‘solid brass’ ($1.99). Pay more, the ‘brass’ screw may snap off as zinc is a brittle metal under stress. ‘Solid brass’ is stronger and the better value. Copper Zinc

Classification of Matter (gas. Liquid, solid, plasma) Separated by PURE SUBSTANCES MIXTURES physical means into Separated by COMPOUNDS ELEMENTS HOMOGENEOUS MIXTURES HETEROGENEOUS MIXTURE chemical means into Kotz & Treichel, Chemistry & Chemical Reactivity, 3rd Edition , 1996, page 31

Elements, Compounds, and Mixtures oxygen atoms hydrogen atoms hydrogen atoms “Elements, Compounds, and Mixtures”   Description: This slide shows the molecular composition of an element, a compound, and two mixtures. Basic Concepts All samples of a substance have the same molecular composition and intensive properties and are homogeneous. Elements and compounds are substances; mixtures are not. The elements making up a compound combine in fixed ratios. Mixtures can be separated by physical methods. Mixtures that have a uniform composition throughout are homogeneous; those that have parts with different compositions are heterogeneous. Teaching Suggestions Use this transparency to help students visualize the molecular composition of elements, compounds, and mixtures and to review the definitions of these terms. Make sure students understand the difference between the terms matter and substance. Remind students that elements and compounds are always homogeneous, while mixtures can be either homogeneous or heterogeneous. Questions: Which of the bottles pictured above contain(s) matter? Which contain(s) a single substance? Explain your answers. How many elements are present in each molecule of water shown in bottle (b)? What is the relative number of atoms of each element in a water molecule? As you know, ice is frozen water. In other words, ice and water are the same substance, in different phases. What would you expect the ratio of hydrogen atoms to oxygen atoms to be in a molecule of ice? Explain your reasoning. Bottle (c) and bottle (d) both contain mixtures. How are these mixtures similar? How are they different? Suppose you find an unlabeled bottle containing a clear liquid. Can you tell by looking at it whether the material is a compound or a mixture? Explain your answer. How can you prove that a sample of sea water is a mixture? Classify the following items as elements, compounds or mixtures; rice pudding, copper, carbon dioxide, air, milk, magnesium chloride, granite, mercury, and maple syrup. A chocolate-chip cookie with more chips in one part of the cookie than another can be used to demonstrate a heterogeneous mixture. Name two other materials that can be classified as heterogeneous mixtures. Explain your reasoning. (a) an element (hydrogen) (b) a compound (water) (c) a mixture (hydrogen and oxygen) (d) a mixture (hydrogen and oxygen) Dorin, Demmin, Gabel, Chemistry The Study of Matter , 3rd Edition, 1990, page 68

Classify the following as element, compound, solution, or heterogeneous mixture Copper H2O Salt in water Air Sand in water Sulfur

Separation of Mixtures Filtration Distillation Crystallization Chromatography

Filtration Filter paper placed in a funnel is used to separate a solid from a liquid. The solid will stay on the filter paper and the liquid flows through the paper to a collection beaker below.

The solution is boiled and steam is driven off. Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 39

Separation of a sand-saltwater mixture. Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 40

Crystallization Formation of a pure solid from a solution. An example of this is rock candy.

Paper Chromatography Separates the parts of a mixture as it travels across the surface of another material.

Conservation of Mass Mass cannot be created or destroyed.

Mass of Reactants=Mass of Products (reactants) (products) Magnesium + Oxygen  Magnesium Oxide 10.0 g + ??  16.6 g How much oxygen reacts with the magnesium to form the magnesium oxide?

Pure Substances Law of Definite Composition A given compound always contains the same, fixed ratio of elements. Law of Multiple Proportions Elements can combine in different ratios to form different compounds. Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

Two different compounds, each has a definite composition. Pure Substances For example… Carbon, C Oxygen, O Carbon monoxide, CO Carbon, C Oxygen, O Oxygen, O Carbon dioxide, CO2 Two different compounds, each has a definite composition. Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

Sucrose The formula is C6H12O6 Every sample of sucrose contains 42.1% carbon, 6.48% hydrogen and 51.4% oxygen.