Chapter 2 Matter and Change . 2.2 Mixtures 2.1 Properties of Matter 2.3 Elements and Compounds 2.4 Chemical Reactions Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

How can mixtures be classified? Classifying Mixtures Describing Matter How can mixtures be classified? A mixture is a physical blend of two or more components. Based on the distribution of their components, mixtures can be classified as heterogeneous mixtures or homogeneous mixtures. A mixture in which the composition is not uniform throughout is a heterogeneous mixture. Example mixing water and oil. A homogeneous mixture is a mixture in which the composition is uniform throughout. Examples oil and vinegar. Another name for a homogeneous mixture is a solution. Many solutions are liquids. But some are gases, like air. And some are solids, like stainless steel, which is a mixture of iron, chromium, and nickel. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Describing Matter The term phase is used to describe any part of a sample with uniform composition and properties. By definition, a homogeneous mixture consists of a single phase. A heterogeneous mixture consists of two or more phases. When oil and vinegar are mixed, they form a heterogeneous mixture with two layers, or phases. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

At the beach, you realize that both ocean water and sand are mixtures At the beach, you realize that both ocean water and sand are mixtures. Which is a homogeneous mixture (or solution)? Which is a heterogeneous mixture? Salt water is a homogeneous mixture, or solution. Sand is a heterogeneous mixture. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

How can mixtures be separated? Separating Mixtures Separating Mixtures How can mixtures be separated? To separate a mixture of olive oil and vinegar, for example, you could decant, or pour off, the oil layer. Or, you might cool the mixture until the oil turned solid. Pouring off the oil layer takes advantage of the fact that oil floats on water. Cooling until the oil layer turns solid takes advantage of a difference in the temperatures at which the olive oil and vinegar freeze. Differences in physical properties can be used to separate mixtures. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Separating Mixtures Filtration The process that separates a solid from a liquid in a heterogeneous mixture is called filtration. Separate base on particle size. Filter paper used in a laboratory is similar to coffee filters. Filter paper is often placed in a funnel. Then the mixture is poured into the funnel. Solid particles that cannot pass through the filter remain in the funnel. The rest of the particles pass through. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Distillation Separating Mixtures . During a distillation, a liquid is boiled to produce a vapor that is then condensed into a liquid. Separate base on differences in boiling point. The figure below shows an apparatus used to perform a small-scale distillation. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Distillation Separating Mixtures As water in the distillation flask is heated, water vapor forms, rises in the flask, and passes into a glass tube in the condenser. The tube is surrounded by cold water, which cools the vapor to a temperature at which it turns back into a liquid. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Distillation Separating Mixtures As water in the distillation flask is heated, water vapor forms, rises in the flask, and passes into a glass tube in the condenser. The tube is surrounded by cold water, which cools the vapor to a temperature at which it turns back into a liquid. The liquid water is collected in a second flask. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Distillation Separating Mixtures The solid substances that were dissolved in the water remain in the distillation flask. This is because their boiling points are much higher than the boiling point of water. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Which physical property does filtration rely on to separate mixtures Which physical property does filtration rely on to separate mixtures? Which does distillation rely on? Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Which physical property does filtration rely on to separate mixtures Which physical property does filtration rely on to separate mixtures? Which does distillation rely on? Filtration relies on the size of a particle, or molecule, of a substance. Distillation relies on the boiling point of the substance. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Differences in physical properties can be used to separate mixtures. Key Concepts Mixtures can be classified as heterogeneous mixtures or as homogeneous mixtures, based on the distribution of their components. Differences in physical properties can be used to separate mixtures. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Glossary Terms mixture: a physical blend of two or more substances that are not chemically combined heterogeneous mixture: a mixture that is not uniform in composition; components are not evenly distributed throughout the mixture homogeneous mixture: a mixture that is uniform in composition; components are evenly distributed and not easily distinguished solution: a homogeneous mixture; consists of solutes dissolved in a solvent Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

phase: any part of a sample with uniform composition and properties Glossary Terms phase: any part of a sample with uniform composition and properties filtration: a process that separates a solid from the liquid in a heterogeneous mixture distillation: a process used to separate components of a mixture using differences in boiling points Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

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