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

Physical Changes in Matter A change in a substance that does not change the identity of the substance Includes all changes of state (changing from solid- liquid-gas) Key Words: Grinding Dissolving Cutting Breaking Shattering

Chemical Changes in Matter Chemical Change is an action where a new form of matter is created by rearranging atoms from the original matter. A new form of matter is created. A chemical change does not change the amount of matter present Examples: Splitting water into hydrogen and oxygen Burning a piece of wood Combining an acid and a base to produce salt and water. Digesting food Popping firecrackers Milk souring if not refrigerated

Signs of Chemical Change You might have a chemical change if you see:  Bubbles (a new gas was formed)  A new odor is detected  Light is given off  A sound is heard  Tarnish appears  There is a change in temperature (Hot or Cold)  A precipitate was formed (a solid is formed from two liquids)  Color change ( ***But not always!)

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

States of Matter There are three states of matter Solids, liquids, and gases that are all different states of matter. Each of these states is also known as a phase.

States of Matter A "phase" describes a physical state of matter. The key word to notice is physical. Things only move from one phase to another by physical means. If energy is added (like increasing the temperature) or if energy is taken away (like freezing something), you have created a physical change.

Particle Movement In Matter SolidsLiquidsGases

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

Liquid  indefinite shape  definite volume  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.

Plasma They are different and unique from the other states of matter. Plasma is different from a gas, because it is made up of groups of positively and negatively charged particles. Not naturally occurring In neon gas, the electrons are all bound to the nucleus. Example: In neon plasma like inside a neon light, the electrons When the light is turned on, the electricity flows through the tube. The electricity charges the gas and creates plasma inside of the tube. The plasma glows a special color depending on what kind of gas is inside. are free to move around the system.