Physical and Chemical Changes NEXT
Physical Change “The physical properties of a substance change, but the identity of the substance does not change.” NEXT
Chemical Properties A chemical property is any characteristic that gives a substance the ability to undergo a change that results in a new substance. 4 Examples of chemical properties: Reacts to water Reacts to light Reacts to oxygen Flammability
Chemical Change “A change in the identity of a substance due to the chemical properties of that substance. A NEW substance or substances are formed as a result of the change.” NEXT
Signs of a Chemical Change Bubbles Production of Heat Light Smoke Change in Color Sound NEXT
Is a chemical change reversible? A chemical change can only be reversed by a chemical reaction, not by physical means.
Are these examples chemical or physical changes? NEXT
A Rusting Bicycle ANSWER
Chemical Change Oxygen in the air reacts with the metal of the bicycle. This produces a new substance called rust. NEXT
Melting Butter for Popcorn ANSWER
Physical Change Heating causes the butter to change from a solid to a liquid. The identity of the butter does not change. NEXT
Hammering Wood Together to Build a Birdhouse ANSWER
Physical Change Hammering the wood together causes the wood to change shape. The identity of the wood does not change. NEXT
Spoiling Food ANSWER
Chemical Change Spoiling food changes color and has a foul odor. Bacteria, mold, enzyme action, and oxidation cause spoilage. NEXT
Mixing Lemonade Powder into Water ANSWER
Evaporating the water separates the ingredients. Physical Change After mixing the lemonade powder and water, lemonade powder and water are still present. Evaporating the water separates the ingredients. NEXT
Mowing the Lawn ANSWER
Cutting the grass does not change the identity of the grass. Physical Change Cutting the grass does not change the identity of the grass. NEXT
Fireworks Exploding ANSWER
Chemical Change Fireworks are composed of different metals, such as copper. After ignited, the fireworks produce light, heat, and sound. NEXT
Water Boiling ANSWER
Physical Change When water boils, water changes from a liquid to a gas. The identity of the water does not change. NEXT
Photosynthesis ANSWER
New substances are formed. Chemical Change Plants change carbon dioxide, water, and sunlight into sugar and oxygen. New substances are formed. NEXT
Separating a Mixture of Rocks and Sand ANSWER
Physical Change Separating the rocks from the sand can be done by physical means. The identities of the rocks and sand do not change. NEXT
Adding Food Coloring to Water ANSWER
Physical Change The identities of the substances did not change. Water and food coloring are still present. NEXT
Adding Vinegar to Baking Soda ANSWER
Chemical Change Gas bubbles were produced. The baking soda and vinegar reacted to form bubbles of carbon dioxide. HOME
Can HEAT cause a chemical reaction? YES !
Can LIGHT cause a chemical reaction? YES, Photosynthesis
change phase (solid, liquid, gas) What is a sign of a physical change? A change in a physical property: Shape, size, length, change phase (solid, liquid, gas)
SIGNS OF A CHEMICAL CHANGE: HEAT LIGHT SMOKE BUBBLES COLOR CHANGE SOUND NEW IDENTITY CAN’T BE REVERSED BY PHYSICAL MEANS
What is….? A change in the identity of a substance due to the chemical properties of that substance. Chemical change
What is….? Any characteristic of a material that can be observed or measured without changing the identity of the material. Physical property
Any characteristic that gives a substance the ability to undergo a change that results in a new substance. Chemical Property
Physical Property What is….? Any characteristic of a material that can be observed without changing the identity of the material. Physical Property
Examples of Physical Properties: Boiling point freezing point Melting point Volume shape Density length Color Mass
Examples of Chemical Properties: Flammability Reacts with oxygen Reacts with H20 Ability to change with light
A ___________change results in a new substance, with a new…. IDENTITY