Unit 2 Concepts of Matter C.4.A differentiate between physical and chemical changes and properties

Table of Contents Slide 3 Definition of Matter and Substance Slides 4 & 5 Physical Properties Slide 6 Chemical Properties Slide 7 Physical Change Slide 8 & 9 Chemical Change Slides 10 – 15 States of Matter

Matter Matter is defined as anything that has mass and takes up space chemists use characteristic properties to tell substances apart and to separate them a substance is matter that has a uniform and definite composition

Physical Property Any quality or condition of a substance that can be observed or measured without changing the substances identity. Physical properties can be classified as Intensive and Extensive properties.

Identify Intensive and Extensive Properties Intensive Property is a physical property of the system that does not depend on the system size or the amount of material in the system. Examples of intensive properties include: * temperature * viscosity * density * electrical resistivity * melting point * boiling point * pressure * spectral absorption maxima (in solution) * flammability Extensive Property an extensive property of a system does depend on the system size or the amount of material in the system. Examples of extensive properties include: * mass * volume * entropy * energy * electrical resistance * texture * heat

Chemical Properties Chemical Property is how a substance reacts in the presence of: Air Acids Water Bases Chemicals Chemical Property is also, how does the substance reacts when it is heated?

Physical Changes in Matter Ex. grinding, cutting, melting, boiling change in a substance that doesn’t change the identity of the substance Includes all changes of state (physical changes of a substance from one state to another)

Chemical Changes in Matter Chemical Change is a change in which a substance is converted into a different substance doesn’t change the amount of matter present reactants – substances that react products – substances that form

Signs of Chemical Change Energy is always absorbed or given off Change in color or odor Production of a gas Irreversibility

States of Matter Solid Liquid Gas

Particle Movement In Matter Solids Liquids Gases

Solid definite volume definite shape atoms are packed together in fixed positions only vibrate in place Not easily compressible little free space between particles

Liquid definite volume indefinite shape atoms are close together not easily compressible little free space between particles

Gases indefinite volume and shape atoms move quickly atoms are far apart compressible lots of free space between particles vapor refers to the gaseous state of a substance that is a solid or liquid at room temperature.

Is It Chemical or Physical Change? Cookies are baked Water boils Salt dissolves in water Milk spoils A metal chair rusts Paper is torn A tree burns down