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Chemistry2.2. Mixtures. 2.2. 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. 2.2.
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Mixtures 2.2 • 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.
2.2 Classifying Mixtures • Classifying Mixtures • How can mixtures be classified?
2.2 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.
2.2 Classifying Mixtures • Based on the distribution of their components, mixtures can be classified as heterogeneous mixtures or as homogeneous mixtures.
2.2 Classifying Mixtures • Heterogeneous Mixtures • A mixture in which the composition is not uniform throughout is a heterogeneous mixture.
2.2 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)
2.2 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.
2.2 Classifying Mixtures • When oil and vinegar are mixed they form layers, or phases. The oil phase floats on the water phase.
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
for Conceptual Problem 2.2 Problem Solving 2.10 Solve Problem 10 with the help of an interactive guided tutorial.
2.2 Separating Mixtures • Separating Mixtures • How can mixtures be separated?
2.2 Separating Mixtures • Differences in physical properties can be used to separate mixtures.
2.2 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.
2.2 Separating Mixtures • Distillation • During a distillation, a liquid is boiled to produce a vapor that is then condensed into a liquid.
Question! • Describe a method that could be used to separate the following mixtures. • Iron filings and sand • Ans. A magnet can be use to draw the filings out of the sand.
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
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
Question Continued • d. Helium and oxygen gases • Ans: cool the gas mixtures until it condenses , then distill the condensate.
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
2.2 Section Quiz. • 1. Which of the following phrases describes a mixture? • composition varies • composition may vary • components cannot be separated
2.2 Section Quiz. • 2. Which of the following is a homogeneous mixture? • vinegar • iron filings in sand • chicken noodle soup • muddy water
2.2 Section Quiz. • 3. Which technique is used to separate homogeneous mixtures? • filtration • distillation • magnetism • dissolving
Homework • Page 58 Write out question. • 39, 42, 46, 43, 38
