Physical and Chemical Properties and Changes

PHYSICAL AND CHEMICAL PROPERTIES AND CHANGES Name _____Key_______________________ PHYSICAL PROPERTY 1. observed with senses 2. determined without destroying matter CHEMICAL PROPERTY 1. indicates how a substance reacts with something else 2. matter will be changed into a new substance after the reaction Identify the following as a chemical (C) or physical property (P): ___P__1. blue color ___P__2. density ___C__3. flammability (burns) ___C__4. solubility (dissolves) ___C__5. reacts with acid ___C___6. supports combustion ___P__7. sour taste PHYSICAL CHANGE 1. a change in size, shape, or state 2. no new substance is formed ___C_8. melting point ___C__ 9. reacts with water ___P__10. hardness ___C_11. boiling point ___p__12. luster ___P__13. odor __C_ _14. reacts with air CHEMICAL CHANGE 1. a change in the physical and chemical properties 2. a new substance is formed Identify the following as physical (P) or chemical (C) changes. __C__1. NaCl (Table Salt) dissolves in water. __C__2. Ag (Silver) tarnishes. ___P_3. An apple is cut. ___P__4. Heat changes H2O to steam. __C__5. Baking soda reacts to vinger. __C__6. Fe (Iron) rusts. __P__7. Alcohol evaporates . __P__8. Ice melts. ___C___9. Milk sours. ___C__10. Sugar dissolves in water. ___C__11. Wood rots. ___C__12. Pancakes cook. ___P__13. Grass grows. ___P__14. A tire is inflated. __C__15. Food is digested. __P____16 . Paper towel absorbs water. Physical and Chem ical Changes Part A Can you recognize the chemical and physical changes that happen all around us? If you change the way something looks, but haven’t made a new substance, a physical change (P) has occurred. If the substance has been changes into another substance, a chemical change (C) has occurred. 1. P An ice cube is placed in the sun. Later there is a puddle of water. Later still the puddle is gone. 2. C Two chemical are mixed together and a gas is produce. 3. C A bicycle changes color as it rusts. 4. P A solid is crushed to a powder. 5. C Two substances are mixed and light is produced. 6. C A piece of ice melts and reacts with sodium. 7. P Mixing salt and pepper. 8. P Chocolate syrup is dissolved in milk. 9. C A marshmallow is toasted over a campfire. 10. P A marshmallow is cut in half. Part B Read each scenario. Decide whether a physical or chemical change has occurred and give evidence for your decision. The first one has been done for you to use as an example. Physical or Chemical Change? Scenario Evidence… Umm! A student removes a loaf of bread 1. hot from the oven. The student cuts a slice off the loaf and spreads butter on it. Physical The bread is just cut in a different shape Your friend decides to toast a piece of 2. The burnt bread is releasing heat and smoke bread, but leaves it in the toaster too long. The bread is black and the kitchen if full of Chemical smoke. 3. 4. 5. 6. You forgot to dry the bread knife when you washed it and reddish brown spots appeared on it. You blow dry your wet hair. The knife is rusting, so that means Chemical P The heat is evaporating the water, but it is still water as water vapor In baking biscuits and other quick breads, the baking powder reacts to release carbon dioxide bubbles. The carbon dioxide bubbles cause the dough to rise. You take out your best silver spoons and Chemical The baking powder is reacting with the ingredients to release carbon dioxide, which is being created notice that they are very dull and have some black spots. Chemical Silver tarnishing is Physical The wire is still the wire, just in a different shape 7. A straight piece of wire is coiled to form a spring. 8. Food color is dropped into water to give it color. Chewing food to break it down into smaller The food is still the same, just smushed together and broken up. 9. particles represents a _________ change, but the changing of starch into sugars by Physical, chemical Stomach acid is reacting with the food, so it would be chemical enzymes in the digestive system represents a ___________change. In a fireworks show, the fireworks explode giving off heat and light. 10. Chemical The chemicals are giving off heat and light that wasn’t previously there, so it is chemical Part C: True (T) or False (F) 1. F 2. F In a physical change, the makeup of matter is changed. 3. T Evaporation occurs when liquid water changes into a gas. 4. T Evaporation is a physical change. 5. F Burning wood is a physical change. 6. F Combining hydrogen and oxygen to make water is a physical change. 7. T Breaking up concrete is a physical change. 8. F Sand being washed out to sea from the beach is a chemical change. 9. F When ice cream melts, a chemical change occurs. 10. F Acid rain damaging a marble statue is a physical change. Changing the size and shapes of pieces of wood would be a chemical change.