Matter Chapter 2

Overview Learn about the composition of matter Learn the difference between elements and compounds Learn to distinguish between physical and chemical properties and changes Learn to distinguish between mixtures and pure substances Learn to methods of separating mixtures

Matter Can exist in three states – solid, liquid and gas Can be described in terms of its physical and chemical properties

Figure 2.7: The three states of matter: Solid. Notice the molecules of a solid are very close together and are not moving fast.

Figure 2.7: The three states of matter: Liquid The molecules of a liquid are further apart from each other and are moving faster than that of a solid.

Figure 2.7: The three states of matter: Gas. Molecules of a gas are very far from each other and moving very fast.

Element Compound Substance Solution Matter Homogeneous Mixture Colloid Heterogeneous Suspension

Classification of Matter

Homework Read Chapter 2 Answer the Focus questions at the end of selected Sections (pages 29 & 41)

Figure 2.18: The organization of matter. Matter is the big picture. It is divided up into 2 major parts  mixture and pure substances. Mixtures may be separated by physical methods  filtration, distillation, by sight. Compounds may be separated into its elemental parts by chemical methods  electrolysis . Elements can not be separated by physical nor chemical methods. Nuclear reactions are the only way to break into elements.

Elements and compounds Atoms – tiny particles that make up matter Elements are made of atoms No two elements are made of the same atoms Made of one type of atom Compounds are made of molecules that are made of two or more different atoms bonded together A specific compound consists of the same particles throughout Molecules are made of atoms that are “stuck” together bonded. CO2 Always have the same composition  same combination of atoms. Elements are found on the Periodic Table of Elements. Compounds are not. No matter where you find a compound it is the same combination of elements whether it be here in Chattanooga or Russia.

Top Ten You are responsible for this information in this orderfor your next test

Figure 2.5: The three allotropes of the element carbon: Diamond. Notice the structure. Pressure of the earth and time has played an important role in this structure. The molecule looks like a diamond.

Figure 2.5: The three allotropes of the element carbon: Graphite. Notice the structure. Layers of crystals.

Figure 2.5: The three allotropes of the element carbon: Buckminsterfullerene. Notice the structure. It is a ring.

Compounds Carbon monoxide and carbon dioxide are both made of carbon and oxygen but in different combinations. Water and hydrogen perioxide are the same way.

Oral Quiz Element or compound Oxygen Carbon Carbon monoxide Sugar nylon Copper wire Silver nitrate Lead Salt Magnesium strips

Chemical properties Describe a substance’s ability to undergo a change to a different substance

Physical properties Are the characteristics a substance exhibits as long as no chemical change occurs.

Physical change Involves a change in one or more physical properties, but no change in composition. The most common physical changes are changes of state: solid  liquid gas

Chemical change Transforms a substance into a new substance or substances Involves a change in the fundamental components of the substance A given substance changes into a different substance or substances Are called reactions Ex. Silver tarnished by reacting with substances in the air Ex. A plant form a leaf by combining various substances from the air and soil

Figure 2.8: Electrolysis, the decomposition of water by an electric current, is a chemical process.

Mixture Has variable composition Homogeneous mixture (solution) Has the same properties throughout Ex. tea, sugar water, glass, alloys Heterogeneous mixture Does not have the same properties throughout Ex.  granite, salt & pepper, Italian dressing

Figure 2.9: The composition of air.

Chart examining each substance of air.

Figure 2.10: Twenty-four-karat gold is an element Eighteen-karat gold is an alloy. Fourteen-karat gold is an alloy.

Figure 2.17: Separation of a sand-saltwater mixture.

Figure 2.16: Filtration separates a liquid from a solid.

Setup to boil water.

Figure 2.15: No chemical change occurs when salt water is distilled.

Figure 2.14: The solution is boiled and steam is driven off.

Figure 2.14: Salt remains after all water is boiled off.

Pure substances Two types Elements Compounds Which cannot be broken down chemically into simpler substances Composed of tiny particles called atoms. Each element has a characteristic type of atom. All elements are on the Periodic table of elements Compounds Which can be broken down chemically into elements Are composed of different types of atoms. Contain molecules  particles that are composed of atoms bonded to one another Ex. Sugar, gasoline, baking soda, plastics

Figure 2.11: Representation of H2O molecules.

Mixtures quiz - Classify as Homogeneous/heterogeneous or pure substance A multivitamin tablet The blue liquid in your car’s windshield washer A Spanish omelet A diamond Gasoline A jar of jelly beans Chunky peanut butter Margarine

Classzone.com Go to classzone.com Click on science  to find your book the state of Tennessee World of Chemistry  Chapter 2 Flip through the flashcards Take Test 1  Bring results to class tomorrow.

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Physical and Chemical Changes Quiz Iron metal is melted. Wood burns in air A rock is broken into small pieces. Milk turns sour. Iron combines with oxygen to form rust. The inside of an apple turns brown when exposed to air. You make scrambled eggs. You step on a piece of chalk and it becomes powdered. You use a flashlight when the electricity goes out. Steam from hour hot shower condenses on a cold mirror.

Physical or Chemical property Quiz The boiling point of a certain alcohol is 780 C. A diamond is very hard Sugar ferments to form alcohol. A gold wire can be flattened and used for foil Gallium metal melts in your hand Platinum does not react with oxygen at room temperature. A dead tree gets chopped for firewood. The copper sheets that form the “skin” of the Statue of Liberty have acquired a greenish coating over the years.