States of Matter Chapter 3

Matter: Anything that has mass (amount of matter) volume (amount of space taken up)

A: Solid Has a definite shape and a definite volume Solids have these characteristics because: Molecules or atoms in a solid move slowly and are strongly attracted to each other

Types of Solids: Crystalline – very orderly, 3 dimensional arrangement of molecules Example: salt, sugar, snow, ice, diamond Amorphous – molecules are in no particular order, random Example: rubber, plastics, wax

2. Solids can change directly from a solid to a gas by sublimation Ex: dry ice

B: Liquid Has a definite volume but no definite shape Liquids have these properties because : Molecules (atoms) in a liquid move faster and are weakly attracted to each other. Liquids are an example of a fluid because they flow (molecules are able to slide past one another).

1)Viscosity some liquids have a stronger attraction between their molecules than other liquids. When a liquid has molecules with these strong attractions, scientists say that the liquid is viscous (this is a physical property)

2)Surface Tension Another property of liquids is surface tension which is what causes liquids to “bead” up or stick together

C: Gas Has no definite shape or volume Gases have these characteristics (properties) because: Molecules in a gas move very fast and are very weakly attracted to each other Gases are free flowing

Gas When a gas fills a container, it pushes against the sides of the container. This is called pressure. Pressure is measured with a pressure gauge. The standard unit for pressure is psi or pounds per square inch

Gas The pressure of a gas can be changed depending on it’s temperature, the amount of matter (mass) and the space it has (volume)

D: Plasma Plasma occurs when: an ionized gas is superheated You would find this state of matter in stars (including our sun) At the core of a nuclear reactor Jet engines Aurora (northern and southern lights) lightning

Plasma Very hot very low density Electrons have separated from their nucleus and orbit more randomly

III. Matter can change in 2 ways A. Chemical change – a change in matter that produces new substances with new properties B. Physical changes in matter can be caused by changes in the amount of energy matter has

IV. Physical changes in matter can be caused by changes in the amount of energy that the matter has. A. Energy causes matter to change form. B. Thermal energy is: the total energy of all of the particles in an object

C. Energy and matter never disappear, they simply change forms.

D. When thermal energy is added to or taken away from matter, the following things will happen: 1. If energy is added or absorbed an endothermic change takes place and these physical changes occur: a. Temperature will increase b. Speed of particles will increase c.Volume will increase d. Solids will change to liquids. This process is called melting and occurs at the melting point

E.Liquids will change to gases. This process is called vaporization Two types of vaporization are: Evaporation happens below the boiling point on the surface of a liquid Boiling is the rapid conversion of liquid to a gas that happens throughout the liquid occurs at the boiling point

F. In a gas, the pressure will increase G. In certain solids if the surface particles gain enough energy they can escape the solid state and become a gas, they do not pass through the liquid state. This is called sublimation.

2. If energy is removed or taken away an exothermic change takes place and these physical changes occur: a. Temperature will decrease b.Speed of particles will decrease c.Volume will decrease d.Gases change to liquids, this process is called condensation e.Liquids will change to solids. This process is called freezing. f.In a gas, the pressure will decrease

Boyle’s Law For a fixed amount of gas at a constant TEMPERATURE: when pressure increases, volume decreases As the molecules are squeezed closer together, they take up less space

Charles’ Law For a fixed amount of gas at a constant PRESSURE When temperature increases, volume increases As the molecules move faster, they bounce off of each other with more force and take up more space