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.

Classifying Mixtures 2.2 How can mixtures be classified?

A mixture is a physical blend of two or more components. 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. You can choose the amount of each item you select from a salad bar. So your salad is unlikely to have the same composition as other salads containing the same items.

2.2 Classifying Mixtures Based on the distribution of their components, mixtures can be classified as heterogeneous mixtures or as homogeneous mixtures.

Heterogeneous Mixtures 2.2 Classifying Mixtures Heterogeneous Mixtures A mixture in which the composition is not uniform throughout is a heterogeneous mixture.

Another name for a homogeneous mixture is a solution. 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)

A homogenous mixture consists of a single phase. 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. Olive oil and vinegar are homogeneous mixtures. The substances in these mixtures are evenly distributed. When olive oil is mixed with vinegar, they form a heterogeneous mixture with two distinct phases.

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.

Separating Mixtures 2.2 How can mixtures be separated?

Differences in physical properties can be used to separate mixtures. 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. 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. A distillation can be used to remove impurities from water. As liquid water changes into water vapor, substances dissolved in the water are left behind in the distillation flask. Inferring What can you infer about the boiling points of substances dissolved in the impure water?

Ans. A magnet can be use to draw the filings out of the sand. 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

Problem

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

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Homework Page 58 Write out question. 39, 42, 46, 43, 38