Outline for Chapter 3 Mixtures, Elements, and Compounds Name Date

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Tobias Patterson
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1 Reading Exercise 3-1 Reading Exercise 3-1 Reading Exercise 3-1

2 Outline for Chapter 3 Mixtures, Elements, and Compounds Name Date I. Mixtures A. There are four main properties of 1. Substances are combined, not combined. 2. The substances in a mixture can be present in amount; there is no set recipe. 3. Substances in a mixture can be separated by. a. Distillation is a process that separates mixture based on the boiling points of the components. Distillation is used to create pure water from salt water, to separate crude oil into its components, like gasoline and kerosene. b. A magnet can be used to separate a mixture where one of the substances is a metal. (Not all metals are magnetic; for instance iron is magnetic and aluminum is not.) c. A centrifuge is a machine that separates mixtures according to their densities. A doctor s office uses a centrifuge to test the iron content in human blood. 4. Because they are physically combined, and not chemically combined, substances maintain their. They may change some of their properties, but they remain the same substance. B. Mixtures are typed according to how well they are mixed together. 1. Heterogeneous mixtures are the, and do not appear to be the. a. Particles are to be seen and to be separated from b. Some mixtures can contain solid and liquids, not just solids. c. Some mixtures, like salad dressing, can be A mixture that appears to be the same throughout is referred to as ; they are well mixed. a. Homogeneous mixtures are mixed together, but the substances are not completely dissolved are called. i. A colloid will not by simply standing (sitting around for a while). ii. They often appear cloudy because colloids light. iii. The 5 names of particular colloids listed on page 64 are,,,, and. b. Another type of homogeneous mixture is created when one substance actually in another. It is called a. i. A solution always contains a and a. ii. The is dissolved. A substance that dissolves in water is said to be. Substances that do not dissolve in water are considered. iii. The universal solvent is. iv. A solution can be separated by means. v. The particles in a liquid solution are too small to scatter light, so the solution appears and. c. Metal solutions are called. This is where is is dissolved in a. Examples of these are and.

3 II. Elements A. Introduction 1. When all the particles are alike the substance is called a pure substance. A pure substance appears the same throughout. 2. Examples of pure substances include iron, aluminum, water, sugar, and table salt. 3. Elements are the simplest type of pure substance because they cannot be broken down to a simpler substance. B. Elements and Atoms 1. The smallest particle of an element that has the properties of that element is an atom. 2. Atoms of the same element are alike. 3. Atoms of different elements are different. C. Chemical Symbols 1. Chemical symbols are a shorthand way of representing the elements. 2. Each symbol consists of one or two letters. The first is always capitalized; the second letter of that same element is never capitalized. III. Compounds A. Introduction 1. Pure substances that are made of more than one element are called compounds. 2. A compound is tow or more elements chemically combined. 3. Compounds can be broken down into simpler substances (called atoms).

4 Activity for Comparing Mixtures to Compounds Name/ date/ class Materials needed for students: Petri dish A few grams of sulfur A few grams of iron filings Magnet Materials needed of teacher: Test tube A few grams of sulfur A few grams of iron filings Heat source (alcohol burner) Test tube clamp Oven mitt Preparing for the activity: Describe 4 properties of a mixture On page 79 of your text, there is a section entitled 3-4 Compounds. Find it and record the first statement written there below. 4 properties of mixture Important property of compounds 1. Activity: For each lab table, the teacher has combined iron filings with sulfur. The sulfur is the yellow stuff. List all the physical properties you can observe in the space provided below. Then read what is stated about the chemical properties. Physical properties Chemical properties and overview of sulfur: Sulphur is found in meteorites, volcanoes, hot springs, and as galena gypsum, Epsom salts, and barite. It is recovered commercially from "salt domes" along the Gulf Coast of the USA. Jupiter's moon Io owes its colors to various forms of sulphur. A dark area near the crater Aristarchus on the moon may be a sulphur deposit. Sulphur is essential to life. It is a minor constituent of fats, body fluids, and skeletal minerals. Melting point is 112 degrees C. Chemical properties and overview of iron: Iron is a relatively abundant element in the universe. It is found in the sun and many types of stars in considerable quantity. Iron nuclei are very stable. Iron is a vital constituent of plant and animal life, and is the key component of hemoglobin. Melting point 1535 degrees celcius The pure metal is not often encountered in commerce, but is usually alloyed with carbon or other metals. The pure metal is very reactive chemically, and rapidly corrodes, especially in moist air or at elevated temperatures. Any car owner knows this. Iron metal has important magnetic properties. Activity continued:

5 Now, gently shake the petri dish so that the 2 elements combine. Based on the properties of mixtures and compounds, what do you think you know are holding? Give support to your response. (In other words, why do you think so?) Using the magnet, carefully separate the 2 elements, if possible. Why do you think this will or will not work? Observe as Ms Wilson combines the two elements and then heats them. Write down all observations here. What is your conclusion in this case? Your conclusion needs to be a paragraph that includes an answer to these questions: Is the substance you worked with a mixture or a compound (hence, the title of this activity)? Is the substance Ms Wilson created a compound or a mixture? Give several reasons for your conclusion. Example of your conclusion (So you will get the idea): The petri dish of combined sulfur and iron is a, while the combination Ms Wilson created is a. This is evident by... If it were not a (compound, mixture), then its properties.

A Matter of Fact. Mixtures, Elements and Compounds

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