Heat conductivity Electrical conductivity Boiling, freezing points Texture Density
Sulfur yellow solid melting point = 112.8°C boiling point = 444.6°C Mercury Silvery heavy, moveable liquid melting point = -38°C boiling point = 356°C Spilled mercury should be cleaned up immediately. Nitrogen dioxide brownish-red gas at room temperature poisonous gas melting point = -9.3°C boiling point = 21°C
What physical properties do you observe in copper? Reddish Has a metallic luster Malleable Good conductor of heat and electricity Density = 8.92 g/ml Melting point : 1085 o C Boiling point: 2570 o C
Chemical Properties Describes how a substance changes into a new substance Ex: 1. Flammability: ability to burn 2. Reactivity: ability to combine with other substance 3. Rusting
What color do you see? Why? Is this a chemical property? Copper forms green copper carbonate when in contact with moist air. Copper forms new substances with nitric acid Copper forms a deep blue solution with ammonia
Comparing Physical and Chemical Properties Substance/MatterPhysical PropertyChemical Property HeliumLess dense than airNonflammable WoodGrainy textureFlammable Baking sodaWhite powderReacts with vinegar to produce bubbles Powdered sugarWhite powderDoes not react with vinegar Rubbing alcoholClear liquidFlammable Red food coloringRed colorReacts with bleach and loses color IronMalleableReacts with oxygen
Chemical or Physical Property? 1.Paper is white 2.Boiling point of H 2 O is 100 o C 3.Zinc reacts with hydrochloric acid and creates hydrogen gas 4.Nitrogen does not burn 5.Sulfur smells like rotten eggs Physical Property Chemical Property
2 types of changes 1. Physical change Keeps chemical composition and properties Does not produce a new substance (change in appearance)
An example of a physical change occurs when making a baseball bat. Wood is carefully crafted into a shape which will allow a batter to best apply force on the ball. Even though the wood has changed shape and therefore physical properties, the chemical nature of the wood has not been altered. The bat and the original piece of wood are still the same chemical substance.
2. Chemical Change Chemical reaction Form new substances with DIFFERENT properties. Change in color, bubbling, light production, smoke, presence of heat, etc…
Chemical changes are changes substances undergo when they become new or different substances. For example, the fireworks we see on the 4th of July are actually metals such as magnesium and copper that change chemically as they light up the night skies with their fantastic colors.
Physical or Chemical Change? Painting Wood PHYSICAL
Physical or Chemical Change? Burning Paper CHEMICAL
Physical or Chemical Change? Digestion of food CHEMICAL
Physical or Chemical Change? Sugar dissolving in water PHYSICAL
Physical or Chemical Change? Iron turning red when heated PHYSICAL
Physical or Chemical Change? Evaporation PHYSICAL
Physical or Chemical Change? A pond freezing in winter PHYSICAL
Physical or Chemical Change? Melting ice PHYSICAL
Physical or Chemical Change? Cutting wire PHYSICAL
Physical or Chemical Change? Painting fingernails PHYSICAL
Physical or Chemical Change? Cutting fabric PHYSICAL
Physical or Chemical Change? Baking muffins CHEMICAL
Physical or Chemical Change? Shattering glass PHYSICAL
Physical or Chemical Change? Decomposition of old leaves CHEMICAL
Physical or Chemical Change? Wrinkling a shirt PHYSICAL
Is this a physical change or a chemical change? Can you find more than one physical or chemical change in the pictures?
Is it Physical or Chemical? ChangePhysicalChemical Melting cheese Burning wood Milk souring (Do all students relate to this?) Wadding up paper Bicycle rusting
Chemical or Physical Change? 1.Bending a Paper Clip 2.Baking a cake 3.The sublimation of carbon dioxide 4.Crushing an aluminum can 5.Vinegar and baking soda combining to create salt and water Physical Change Chemical Change Physical Change
Review: 1.Identify the different phases of matter. 2.The particles of a substance are closest together in a _____. 3.The particles of a substance that does not have a definite volume or shape is 4.Identify an example of a physical change. 5.What are some physical properties of matter? 6.Give 1 example of a chemical property. 7.Explain what happens to a substances when a chemical change occurs.
Writing Activity Write a paragraph about the difference between a chemical and physical change. Give examples of each.