Four States of Matter Chapter 4 – Section 1

Matter – Moving Particles States of Matter – the physical forms of a substance (solid, liquid, gas, or plasma) The state of matter a substance is in depends on the motion of the particles

Solids Solid is a state of matter in which the volume and shape of a substance are fixed. The particles of a solid are closely locked in position and can only vibrate. Crystalline Solids have particles with a regular repeating pattern & have a distinct melting point (sugar, salt, snow, sand). Amorphous Solids have particles that are not arranged in a regular pattern & do not have a distinct melting points (crayons, plastic, rubber).

Liquids Characteristic properties of liquids include: Liquid is a state of matter that has a definite volume but not a definite shape. A liquid takes the shape of its container. The particles of a liquid are able to slide past each other (able to flow). A liquid’s particles are more loosely connected than those of a solid, but packed almost as tightly together. Characteristic properties of liquids include: surface tension - the result of an inward pull among the surface molecules bringing them closer together viscosity – the resistance of a liquid to flow

Gases Gas is a state of matter that does not have a definite volume or shape. The particles of a gas move about freely and collide randomly with each other.

Plasmas Plasma is a state of matter that does not have a definite shape or volume and whose particles can be broken apart Plasmas are able to conduct an electric current, gases can not. More than 99% of the matter in the universe is plasma. On Earth, natural plasmas are found in lightning and fire.

Plasma consists of a collection of free-moving electrons and ions - atoms that have lost electrons. Energy is needed to strip electrons from atoms to make plasma. The energy can be of various origins: thermal, electrical, or light (ultraviolet light or intense visible light from a laser). With insufficient sustaining power, plasmas recombine into neutral gas. Plasma can be accelerated and steered by electric and magnetic fields which allows it to be controlled and applied. Plasma research is yielding a greater understanding of the universe. It also provides many practical uses: new manufacturing techniques, consumer products, and the prospect of abundant energy.

Phases of Matter Chapter 4 – Section 2

Energy and Changes of State A change of state is the change of a substance from one physical state to another. A change of state requires a loss or gain of energy by a substance’s particles.

Melting: Solid to Liquid State Melting is the change of state in which a solid becomes a liquid by adding heat. Particles must absorb (take in) energy. The temperature at which a substance changes from a solid to a liquid is the melting point of the substance.

Freezing: Liquid back to Solid State Freezing is the change of state from a liquid to a solid. Energy must be removed from the liquid to slow the movement of the particles. The temperature at which a liquid changes into a solid is the liquid’s freezing point.

Vaporization: Liquid to Gas State Vaporization is the change of state from a liquid to a gas. Evaporation is the change of a liquid to a gas only at the surfaces of the liquid Boiling is the change of a liquid to a vapor, or gas throughout the liquid. The temperature at which this change happens is the boiling point. Water boils more easily if the atmospheric pressure is lower. Why??

Condensation: Gas back to Liquid Condensation is the change of state from a gas to a liquid. Condensation and vaporization are the opposite of each other. Energy must be removed from the gas to slow the movement of the particles. The condensation point is the temperature at which a gas becomes a liquid.

Sublimation: Solid to Gas State Sublimation is the change of state in which a solid changes directly to a gas. The solid must gain energy for the particles to overcome their attractions. In sublimation, the particles must go from being very tightly packed to being spread far apart.

Deposition: Gas to Solid State Deposition is the change of state in which a gas changes directly to a solid. The gas must lose enough energy for the particles to greatly slow the movement of the particles. In deposition, the particles must go from being very far apart to being very tightly packed together.

Temperature and Changes of State When a substance is undergoing a change of state, its temperature does not change until the change of state is complete. Gas Liquid Solid (Energy)

Using Melting & Boiling Point to Determine State of Matter Substance Melting Point (°C) Boiling Point (°C) Ethanol −114.3 78.4 Sodium Chloride 800.8 1465 Nitrogen -209.86 -195.8 Water 100 Which substance(s) are gases at 500°C ? Which substance(s) are solid at -100 °C? Which substance(s) are liquid at 1000 °C ?