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States of Matter. Completed as a requirement for Maverick Physical Science 2013-2014 C.L., M.P. Molecules in Liquids and Gases. A liquid has definite shape but no definite volume, and they take the shape of their container. The molecules are loosely associated with each other.
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Completed as a requirement for Maverick Physical Science 2013-2014 • C.L., M.P.
Molecules in Liquids and Gases • A liquid has definite shape but no definite volume, and they take the shape of their container. The molecules are loosely associated with each other. • A gas has no definite shape or volume, and they fill their container. The molecules can move freely.
Liquids VS. Gases LIQUIDS The molecules move more slowly, and they slide over each other. GASES The molecules are faster-moving than liquids. They are also farther apart.
Fluids • A fluid is a form of matter that flows or takes the shape of its container • Liquids and gases are fluids • The forces in fluids are more sophisticated due to the fact that fluids take the shape of its container.
Pressure • Pressure is the act of applying force to an object. • When pressure is applied to a solid, the force transmits directly down, unlike what it would do to a fluid. • Pressure is caused by collisions between atoms.
Intermolecular Forces • Intermolecular forces are one of the two forces that act with atoms. They act between atoms. • Intermolecular forces pull atoms together, but separates them when atoms become too close together.
Thermal Energy • While intermolecular forces are pulling molecules closer together, thermal energy causes them to separate slightly when they are too close • Thermal energy is the same as heat. • When molecules have enough thermal energy,, it overcomes the intermolecular forces and the molecule spreads apart.
Melting Point • The melting point is the temperature at which a substance melts, or changes from a solid to a liquid. • Intermolecular forces plays a part in the temperature at which a object melts.
Boiling Point • The boiling point is the temperature at which a substance boil or changes from a liquid to a gas. • Intermolecular forces “disappear” when enough thermal energy is added. (This is how a liquid is changed to a gas.)
Melting and boiling Points Materials have a wide range of melting and boiling points.
Evaporation • Evaporation is the change of a substance from a liquid to a gas below the melting point. • It is a process that takes energy away from a liquid, causing the average energy to be lowered. • The source of evaporation is high-energy molecules.
Condensation • Condensation occurs when molecules change from a gas to a liquid. • Condensation occurs because water vapor molecules with less energy stick to cool surfaces.
Warm air is on top due to the fact that the density of warm air is lower than that of the cooler fluid. Convection Convectionis the circulatory movement in fluids due to warmer portions rising and cooler portions sinking.
The Atmosphere of Earth • The atmosphere of Earth is created by convection of wind currents. • The energy from the sun passes through the atmosphere to the ground. • Earth’s atmosphere is 78% nitrogen, 21% oxygen, and 1% of other elements.
Materials In Solids • The particles in a solid are bound together so tightly that it has a definite shape and size. • Solids keep their shape due to their ability or having definite shape. • Some solids are stronger than others. Ex. Steel is stronger than wood
Molecules in Solids The molecules in a solid are packed more tightly together. They are conjoined by particles that act like springs.
Mechanical properties • The strength of an object is how well it can hold its shape under force. • Elasticity is how far a solid can stretch and then return to its original size.
More mechanical properties • The brittleness of a solid is its ability to break easily and its inability to stretch. • A solid with ductility can bend without breaking and can sometimes be shaped.
Crystalline solids • Crystalline are formed when atoms in a solid are in an orderly repeating pattern. • Most natural occurring solids are crystalline, such as salt (NaCl)
More crystalline solids • Many crystalline are solids in your everyday life. • Crystalline, on a microscopic level, have various patterns. These are two common patterns, hexagonal and square.
polymers • Polymers are materials in which molecules have a pattern. • Some plastics are a type of polymer.
Amorphous solids • Amorphous solids are solids at which the molecules do not have a repeating patters • Plastics belong in the amorphous solids family.
Heat conduction • Heat conduction is the transfer of heat from a high-temperature object to a low-temperature object. • Thermal equilibrium is the condition where temperatures from two objects are the same.
Thermal conductors • Thermal conductors are materials that could easily conduct heat. • Thermal conductors include copper, aluminum, gold, and some other materials. • In a space where no matter exists, conduction cannot occur due to removal of a vacuum.
Thermal insulators • Thermal insulators are materials that could not easily conduct heat. • Thermal insulators include plastic, wood, foam, rubber and some other non-metals.
