Do Now Today we will be discussing the differences between Heterogeneous and Homogeneous mixtures. Copy the following: The words Heterogeneous and Homogeneous have Latin pre-fixes, which mean – Hetero – Different Homo – Same Physical ScienceFebruary 17 th 2011 SWBAT define the difference between a heterogeneous mixture and a homogeneous mixture

Homework Review State the relationship between atoms and elements. Are both atoms and elements matter? – An atom is the smallest unit of an element that has that element’s properties. Both atoms and elements are matter. List two types of pure substances: – Elements – Compounds

Describe matter, and explain why light is not matter. Is light made of atoms and elements? – Matter has mass and takes up space. Light has no mass or volume and no atoms. Define molecule, and give examples of a molecule formed by one element and a molecule formed by two elements – A molecule is the smallest unit of a substance that keeps all physical and chemical properties of a substance. Oxygen (O 2 ) is an example of a molecule formed by one element. Water (H 2 0) is a molecule formed by two elements.

Classify each of the following as an element or compound: – A. Sulfur (S 8 ) Element – B. Methane (CH 4 ) Compound – C. Carbon monoxide (CO) Element – D. Cobalt (Co) Compound State the chemical formula for water. – Water has 2 hydrogen and 1 oxygen atom = H 2 O

Compare and contrast mixtures and pure substances, give an example of each. – A pure substance has the same composition throughout. – A mixture has more than one pure substance.

Mixtures Most matter in the universe is found in mixtures. A mixture is made from two or more substances either elements, compounds or both - that are not chemically combined.

Mixtures and compounds differ in two ways… Substances in a mixture keep their individual properties. Parts of a mixture are not necessarily present in specific ratios.

Compound A compound has properties different than the elements that make it up. The parts of a compound are present in specific ratio’s. + = Hydrogen (g) Water – H20 (l)

Other Compounds

Compounds and Mixtures Most of the matter around you is in the form of compounds or mixtures. Water, carbon dioxide, salt, vinegar, baking soda, lye, sugar, gasoline, and bleach are all chemical compounds.

Heterogeneous Mixture A mixture in which different materials can be easily distinguished. Examples: Pizza, trail mix, beach sand, bird seed, oil & water, dirt

Solutions Homogeneous mixture: is a substance in which two or more substances are uniformly spread out. Solution is another term for homogeneous mixture. Examples: Salt water, gasoline, vinegar, hand lotion

Miscible VS. Immiscible Miscible – when two liquids are mixed together and they are evenly spread. – Gasoline Immiscible – when two liquids do not mix together – Oil & water

Today’s Assignments Classwork – Mixture Worksheet – We will spend approximately 5-7 minutes per section then review it and move on! Homework – “Science and the Consumer” – Page 43 – Read and answer both questions in notebook

Classwork Review 1. Identify each of the following samples of matter as: homogeneous matter or heterogeneous matter (a) spaghetti sauce- heterogeneous (b) table sugar - homogeneous (c) cough syrup -homogeneous (d) glass - homogeneous (e) river water - heterogeneous (f) nitrogen - homogeneous

2. Classify each of the following as: element (ele) or compound (com) or mixture (mix) (a) spaghetti sauce - Mixture (b) table sugar - Compound (c) cough syrup - Mixture (d) silver- Element (Ag) (e) orange juice - Mixture(Water & Oranges) (f) iced tea - Mixture (g) glass - Mixture (h) river water - Mixture (i) nitrogen- Element (N) (j) Phosporous- Element (P) (k) oxygen - Element (O) (l) air - Mixture

3. Choose words from the following list to fill in the blanks in the sentences. mixtureheterogeneous mattersubstance compoundhomogeneous matterelement (a) Matter that has uniform characteristics throughout is called HOMOGENEOUS MATTER (b) Matter that has parts with different characteristics is called HETEROGENEOUS MATTER (c) A simple substance that cannot be broken down into other substances by chemical means is called a(n) ELEMENT (d) A chemical combination of simple substances is called a COMPOUND (e) A physical combination of different substances that retain their individual properties is called a(n) MIXTURE (f) Either an element or a compound may be referred to as a SUBSTANCE

Part 4 "The components of a mixture can be separated by physical means; a compound must be chemically broken apart into its components. A mixture has a variable composition; a compound has a definite composition."

5. Classify these samples of matter as a: substance / homogeneous mixture / heterogeneous mixture (a) copper- Substance (b) ink- homogeneous mixture (c) glue- homogeneous mixture (d) carbon mixed with sand- heterogeneous mixture (e) water containing dissolved salt – homogeneous mixture (f) flower – heterogeneous mixture (g) oxygen dissolved in water – homogeneous mixture (h) apple juice – homogeneous mixture

6. Classify each of the following as a: element / compound / homogeneous mixture / heterogeneous mixture (a) water- compound (b) air- homogeneous mixture (c) sugar dissolved in water - homogeneous mixture (d) granite - - heterogeneous mixture (e) sand in water - heterogeneous mixture (f) peanut butter - heterogeneous mixture (g) carbon- element (h) table salt- compound (i) homogenized milk - homogeneous mixture (j) oxygen- element (k) blood- heterogeneous mixture (l) motor oil - homogeneous mixture

7. Fill in the blanks with: element / compound / homogeneous mixture / heterogeneous mixture (a) Steel contains mostly iron plus trace amounts of at least one other element. You could have heard of various kinds of steel, stainless steel, cobalt steel, tungsten steel. Since the composition of steel can vary, it is a homogeneous mixture. (b) Hydrogen is listed on the periodic table. It is a Element. (c) Milk is a homogeneous mixture because it consists of more than one component, and its composition varies. For example, you have probably seen whole milk, 2% milk, and non-fat milk at the grocery store. These three grades of milk all differ in their fat content. (d) Table salt is composed of the elements sodium (Na) and Chlorine (Cl) in fixed proportions. It is a compound. (e) Seawater contains sodium chloride and many dissolved minerals. The composition of seawater changes from place to place. Some seawater is high in dissolved minerals, but in other regions the seawater is lower in minerals. Since its composition is variable, seawater must be a homogeneous mixture.