States of Matter

States of Matter Chapter 8 – Section 1 States of Matter : the physical forms of matter, which include solid, liquid, and gas. Composed of atoms and molecules. Solid: the state of matter in which the volume and shape of a substance are fixed. The particles in a solid are very close. The particles move but they do not move fast. Have a definite shape and volume. Particles do not move fast enough to overcome the attraction between each other. Two types of solids: Crystalline: orderly and 3D arrangement of particles. Arranged in specific repeating patterns. Amorphous: do not have a special arrangement. Particles are not arranged in a pattern.

States of Matter Chapter 8 – Section 1 Liquid: the state of matter that has a definite volume but not a definite shape. Particles move fast enough to overcome some of the attractions between them. They slide past each other. Special properties of liquids: Surface tension : the force that acts on the surface of a liquid and that tends to minimize the area of the surface. Water and gasoline---what's the difference? Viscosity: the resistance of a liquid to flow. The stronger the attraction the more viscous. Honey is more viscous than water.

Section 1 Gas : a form of matter that does not have a definite volume or shape. Particles move quickly. Less attraction between gas particles than particles of solids or liquids of the same substance. Most attraction between particles is found in a solid. Least is found in a gas.

States of Matter Chapter 8 – Section 2 Temperature : a measure of how hot (or cold) something is; specifically, a measure of the movement of particles. Particles move faster with more heat. Ex. basketball. Volume : a measure of the size of a body or region in three- dimensional space. With a gas it depends on the container the gas is in. Gas can be compressed---shaping balloons. Liquids are not very compressible. Water balloons pop when squeezed. Pressure : the amount of force exerted per unit area of a surface. Number of times the particles of a gas hit the inside of their container. Increased force leads to greater pressure.

States of Matter Chapter 8 – Section 2 Changing either temperature, pressure, or volume will affect the other two components. Boyle’s law: the law that states that the volume of a gas is inversely proportional to the pressure of a gas when temperature is constant. Pressure increases--volume decreases. Charles’s law : the law that states that the volume of a gas is directly proportional to the temperature of a gas when pressure is constant. Air molecules move faster.

States of Matter Chapter 8 – Section 3 Change of State : the change of a substance from one physical state to another---all are physical. Particles in a liquid have more energy than solids. But gas particles have more energy than liquid. To change substances you must add or remove energy. Melting : the change of state in which a solid becomes a liquid by adding energy. Add energy to ice so it melts. As temperature increases the particles move faster. When a solid melts it is called a melting point. Particles must overcome some of their attractions. Melting is endothermic-- -energy is taken in or added to change states.

Section 3 Freezing: from liquid to a solid. Point at which it changes is called its freezing point. Opposite of melting and occur at the same temperature. For a liquid to freeze the attraction must overcome the motion of particles. Remove energy will cause particles to lock in place. Freezing is exothermic---because energy is taken out or removed. Evaporation : the change of a substance from a liquid to a gas. Sweating is a form of evaporation---releases energy to the air but is endothermic. Energy is required to cause the evaporation. Boiling : the conversion of a liquid to a vapor when the vapor pressure of the liquid equals the atmospheric pressure

States of Matter Chapter 8 – Section 3 Atmospheric pressure changes how fast a liquid boils. Water boils at 100C at sea level only. The higher you go the less amount of air pressure. Water boils faster but it takes longer to cook foods in boiling water. 95C is not as hot as 100C. Not as many air molecules above you so less pressure. Condensation : the change of state from a gas to a liquid. The point where it changes is called the condensation point. Same temperature, per substance, as boiling point under a given pressure. Particles clump together and energy must be removed. Condensation is exothermic reaction.

Section 3 Sublimation : the process in which a solid changes directly into a gas. Ex. dry ice. Particles must move from being tightly packed to being spread far apart. Attraction between the particles must be overcome. Endothermic reaction--- energy is gained. When substance lose or gain energy one of two things happen. Its temperature changes or its state changes. Temperature is related to the speed of the particles. Temperature does not necessarily change during the change of state. Deposition: changing from a gas to a solid. Ex. Fire extinguisher or snow.