2. Notes on states of matter

Physical states of matter

Characteristics of states of matterSolid1) Have definite shape and volume.2) substances will resist forces that try and change the volume of the shape.Liquid1) Have definite volume, but can change shape.2) Liquids flow and take shape of the container.Gas1) No definite volume or shape.2) Gasses expand to fill container.Physical state of a substance1) Freezing point- Is the temperature at which a liquid changes its physical state and become a solid.2) Melting point - The temperature at which a solid changes completely into a liquid3) Boiling Point - The temperature at which a liquid changes into a gas or vapor.Changes of stateA change in state occurs: 1) when substances move from one physical state to another.2) A change in the arrangement of particles.3) the absorption or release of energy.Melting1. Change of state from solid to liquid2. for solids to melt the energy of the particles must increase enough to overcome the intermolecular forces holding the particles together.3. Solids held together by strong forces will have a higher melting point than one where the forces are weak.4.More energy/heat is needed to break the intermolecular forcesEvaporation and boiling1. Evaporation- process where a liquid changes to a gas at temperatures below its boiling point.2. A liquid is boiling if there are changes from the liquid to the gas state occurring throughout the liquid.Condensation1) the change in state from gas to liquid.2) particles lose potential energy.3) The intermolecular forces of attraction  become stronger.Freezing1) The change of state from a liquid to a solid.2)When temperature is at freezing point the particles lose potential energy and the intermolecular forces between them become stronger.Sublimation1) The direct change from a solid to a gas on heating and from a gas to a solid on cooling.2) the substance does not go through the liquid state.Cooling CurveCooling curve of water1) As the liquid cools the temp. decreases.2) The particles move slower and have less kinetic energy.3) As the state changes from water to ice the temp. does not change.4) The energy released does not cause the particles to lose kinetic energy at this point.5) The loss of energy causes an increase in the intermolecular forces  that hold the particles together.6)The temp. remains constant. This heat is called latent heat.

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