Physical and Chemical Properties

Physical Property A characteristic of a substance that does not involve a chemical change density, color, or hardness. Examples: Color, Shape, Odor, Weight, Volume, Texture, State, and Density.

General Physical Properties Size Shape Color Smell Weight/Mass Volume

Thermal Conductivity The rate at which a substance transfers heat Example:

Solubility The ability of a substance to dissolve in another substance

Magnetism The property of some materials to attract iron or objects containing iron Lodestone: its naturally attractive! Yay

State/Phase of Matter The physical form in which a substance exists Either a solid, liquid, or gas.

Density The mass per unit volume of a substance.

Malleability The ability of a substance to be rolled or pounded into thin sheets.

Chemical Property Describes a substance’s ability to participate in chemical reactions

Flammability The ability of a substance to burn (no really, that’s the entire definition!)

Reactivity The ability of two or more substances to combine and form one or more new substances Metal + Oxygen =

Comparing Chemical and Physical Properties Physical Properties are easy to observe. You can measure density or hardness and not change anything. It’s fun! Chemical Properties are harder to observe, but that’s okay! Just remember that even though wood may not be burning right this second, it is still considered flammable.

Evidence of Chemical Reactions Color Change: an unusual color change can signal that a new substance has formed. In a chemical change blue and yellow may actually turn red! It’s mind blowing.

Evidence of Chemical Reaction A solid may form (Precipitate) from a solution during a chemical reaction The precipitate is a new or different substance and doesn’t dissolve in the solution. Instead it sinks or floats.

Evidences of a Chemical Reaction A gas is produced and you may see bubbles. Gas may or may not have an odor.

Evidences of a Chemical Reaction Temperature Change: Hold on to your hats, because this means that you may see a temperature change. The heat won’t come from an external source though! It will come from the energy from the reaction!

Evidences of a Chemical Reaction With a chemical reaction, the outcome is very difficult, or even impossible to reverse. Example: Water can melt and go through different state changes. That would be a physical change, but in a chemical reaction the chemical composition would change and wouldn’t be so easy to reverse.