Physical and Chemical Changes Physical Property Observable traits

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Physical and Chemical Changes

Physical and Chemical Changes

Physical Property Observable traits that do not change the identity of the substance ¡

Physical Property Observable traits that do not change the identity of the substance ¡ Include color, shape, smell, taste, mass, volume and density ¡ Also include ductility, malleability, conductivity and solubility ¡ Can be determined without changing a substance ¡

Physical Property Density - mass/volume ¡ Ductility – ability to be pulled into wire

Physical Property Density - mass/volume ¡ Ductility – ability to be pulled into wire ¡ Malleability – ability to be hammered ¡ Conductivity – ability to pass electric current ¡ Solubility – ability to dissolve ¡

Physical Change Any change in size, shape, form, or state where the identity of

Physical Change Any change in size, shape, form, or state where the identity of the matter stays the same ¡ Ex. - Cutting a watermelon into slices ¡ Often easy to reverse with filtration, magnetism, evaporation, distillation, and centrifuge ¡

Physical Change ¡ Evidence includes: l l l l same substance no new substances

Physical Change ¡ Evidence includes: l l l l same substance no new substances color change state change same smell, taste, texture different volume, mass same density

Chemical Property The characteristic of a substance that allows it to change into something

Chemical Property The characteristic of a substance that allows it to change into something different ¡ Includes flammability, reactivity with oxygen, and acidity ¡ Testing for chemical properties causes a change in the substance ¡

Chemical Property Flammability – able to be burned; combustion ¡ Reactivity with oxygen ¡

Chemical Property Flammability – able to be burned; combustion ¡ Reactivity with oxygen ¡ Acidity ¡ l l l p. H level scale from 1 to 14 1 being most acidic 14 being least acidic (most basic) Water is a 7 (neutral) on the p. H scale

Chemical Change Happens when a substance undergoes a change that causes it traits to

Chemical Change Happens when a substance undergoes a change that causes it traits to change ¡ Ex. - digestion, photosynthesis, paint drying, and oil burning. ¡ New materials are formed that are different from the starting materials ¡

Chemical Change NOT easily reversed ¡ Evidence includes: ¡ l l Release of energy

Chemical Change NOT easily reversed ¡ Evidence includes: ¡ l l Release of energy – light, heat, sound Formation of gas or solid that is NOT the results of simple state change

Chemical Change ¡ Evidence includes: l new substance

Chemical Change ¡ Evidence includes: l new substance

Example of Chemical Change ¡ Chlorine l l l Added to swimming pools and

Example of Chemical Change ¡ Chlorine l l l Added to swimming pools and drinking water Causes acidity Prevents reproduction, growth and development of algae, bacteria, protists and insects.

Types of Chemical Reactions Synthesis ¡ Decomposition ¡

Types of Chemical Reactions Synthesis ¡ Decomposition ¡

Acids and Bases ¡ Acids l l ¡ Sharp smell, sour taste Corrode metals,

Acids and Bases ¡ Acids l l ¡ Sharp smell, sour taste Corrode metals, harmful to organisms p. H between 0 and 7 Ex. - citrus fruits contain acids. Bases l l Feel slippery, taste bitter May also be harmful to organisms p. H of between 7 and 14 Ex. - a bar of soap is basic

Salts are compounds of metal and nonmetal ¡ Formed when acids and bases react

Salts are compounds of metal and nonmetal ¡ Formed when acids and bases react ¡ Ex. – table salt and chalk ¡

Energy… ¡ …is required for both types of changes

Energy… ¡ …is required for both types of changes