Chemistry2.2 Slide 1 of 21 2.2 Mixtures Panning is one way to separate gold from a mixture of gold and materials such as sand or gravel. A pan containing the mixture is place underwater and shaken vigorously from left to right. You will learn how to classify and separate mixtures. Slide 2 of 21 © Copyright Pearson Prentice Hall 2.2 Mixtures > Classifying Mixtures Classifying Mixtures How can mixtures be classified? Slide 3 of 21 © Copyright Pearson Prentice Hall 2.2 Mixtures > Classifying Mixtures A mixture is a physical blend of two or more components. A salad bar provides a range of items. Customers choose how much of each item to use in their salads. Each salad has a different composition. Slide 4 of 21 © Copyright Pearson Prentice Hall 2.2 Mixtures > Classifying Mixtures Based on the distribution of their components, mixtures can be classified as heterogeneous mixtures or as homogeneous mixtures. Slide 5 of 21 © Copyright Pearson Prentice Hall 2.2 Mixtures > Classifying Mixtures Heterogeneous Mixtures A mixture in which the composition is not uniform throughout is a heterogeneous mixture. Slide 6 of 21 © Copyright Pearson Prentice Hall 2.2 Mixtures > Classifying Mixtures Homogeneous Mixtures A mixture in which the composition is uniform throughout is a homogeneous mixture. Another name for a homogeneous mixture is a solution. Solution = solvent (lg. amt.) + solute (Sm.amt) Slide 7 of 21 © Copyright Pearson Prentice Hall 2.2 Mixtures > Classifying Mixtures The term phase is used to describe any part of a sample with uniform composition and properties. • A homogenous mixture consists of a single phase. • A heterogeneous mixture consists of two or more phases. Slide 8 of 21 © Copyright Pearson Prentice Hall 2.2 Mixtures > Classifying Mixtures When oil and vinegar are mixed they form layers, or phases. The oil phase floats on the water phase. Slide 9 of 21 © Copyright Pearson Prentice Hall Mixtures > Problem Classify each of the following as a homogeneous mixture or heterogeneous mixture? A brass ( an alloy of zinc and copper) B. A salad C. blood D. powder milk mix dissolved in water Ans.A. and D Homogeneous, b and c heterogeneous © Copyright Pearson Prentice Hall Slide 10 of 21 Slide 11 of 21 © Copyright Pearson Prentice Hall Slide 12 of 21 © Copyright Pearson Prentice Hall Slide 13 of 21 © Copyright Pearson Prentice Hall Practice Problems for Conceptual Problem 2.2 Problem Solving 2.10 Solve Problem 10 with the help of an interactive guided tutorial. Slide 14 of 21 © Copyright Pearson Prentice Hall 2.2 Mixtures > Separating Mixtures Separating Mixtures How can mixtures be separated? Slide 15 of 21 © Copyright Pearson Prentice Hall 2.2 Mixtures > Separating Mixtures Differences in physical properties can be used to separate mixtures. Slide 16 of 21 © Copyright Pearson Prentice Hall 2.2 Mixtures > Separating Mixtures Filtration The process that separates a solid from the liquid in a heterogeneous mixture is called filtration. A colander is used to separate pasta from the water in which it was cooked. This process is a type of filtration. Slide 17 of 21 © Copyright Pearson Prentice Hall 2.2 Mixtures > Separating Mixtures Distillation During a distillation, a liquid is boiled to produce a vapor that is then condensed into a liquid. Slide 18 of 21 © Copyright Pearson Prentice Hall Mixtures > Question! Describe a method that could be used to separate the following mixtures. a. Iron filings and sand b. Ans. A magnet can be use to draw the filings out of the sand. Slide 19 of 21 © Copyright Pearson Prentice Hall Mixtures > Question continued b. sand and salt Ans: add water to the mixture to dissolve the salt. Filter the mixture to remove the sand and then boil off the water so only the salt remains Slide 20 of 21 © Copyright Pearson Prentice Hall Mixtures > Question continued c.The components of ink Ans: paper chromatography should be used to separate the components of the ink. Or Distillation if enough ink is available Slide 21 of 21 © Copyright Pearson Prentice Hall Mixtures > Question Continued d. Helium and oxygen gases Ans: cool the gas mixtures until it condenses , then distill the condensate. Slide 22 of 21 © Copyright Pearson Prentice Hall Mixtures > Question A mixture is the chemical bonding of two or more substances in any proportion. Is this statement true or false. Explain Ans: False Mixtures are a physical blend of substances, not a chemical bonding of substances Slide 23 of 21 © Copyright Pearson Prentice Hall Mixtures > Problem Slide 24 of 21 © Copyright Pearson Prentice Hall 2.2 Section Quiz. 1. Which of the following phrases describes a mixture? a. composition varies b. composition may vary c. components cannot be separated Slide 25 of 21 © Copyright Pearson Prentice Hall 2.2 Section Quiz. 2. Which of the following is a homogeneous mixture? a. vinegar b. iron filings in sand c. chicken noodle soup d. muddy water Slide 26 of 21 © Copyright Pearson Prentice Hall 2.2 Section Quiz. 3. Which technique is used to separate homogeneous mixtures? a. filtration b. distillation c. magnetism d. dissolving Slide 27 of 21 © Copyright Pearson Prentice Hall END OF SHOW Homework • Page 58 Write out question. • 39, 42, 46, 43, 38