Physical & Chemical Properties Physical Science Mr. Willis

Physical Property Any aspect of an object or substance that can be measured or perceived without changing its identity. Examples:

Density D = m/V

Boiling Point The temperature at which a liquid changes to a gas. For water: 100 o C

Freezing Point The temperature at which a liquid changes to a solid. For water: 0 o C

Odor

Color

Shape

Chemical Property Any of a material's properties that becomes evident during a chemical reaction; that is, any quality that can be established only by changing a substance's chemical identity. Examples:

pH How acidic or basic a substance is…

Electronegativity the ability of an atom to attract electrons towards itself in a covalent bond

Reactivity with other substances

Flammability

Oxidation state

Bond preference

Physical Change vs. Chemical Change Physical Change …doesn’t change what the substance is. Ex. Cut paper and it is still paper …can be reversed Ex. Dissolved sugar in water can be separated through evaporation Chemical Change …a new substance is formed and energy is either given off (exothermic) or absorbed (endothermic) Ex. Burn paper & it is no longer paper …cannot be reversed without extraordinary means, if at all. Ex. Sugar mixed and baked in a cake cannot be separated easily

Signs that a Chemical Change has Occurred Bubbles of gas appear A precipitate(solid) appears where there was only liquid before Change in color Change in Temperature