Boiling: The change of state from liquid to gas with an increase in thermal energy, to the substance's boiling point. The liquid becomes a gas because the particles are able to spread apart enough to change from a liquid phase to a gaseous phase.
Boiling Point: The temperature at which boiling occurs in a certain liquid, e.g. water's boiling point is 100ºC at the pressure of 1 atm., as boiling point increases as pressure increases due to the pressure exerted on the particles changing their ability to spread and boil.
Condensing: The change of state from gas to liquid. This happens when a gas cools, often upon colliding with a solid surface, so the particles collect and become more dense until they change physical state.
Freezing: A change of state from liquid to solid. When the particles lose kinetic energy they move less and become more densely packed. Attractions between the particles cause bonds or intermolecular forces form between the particles to keep them in fixed positions.
Gas: A state of matter in which the particles move randomly in different directions, colliding with other particles and surfaces and changing direction. The particles are spread over a wide space; it is the least dense state of matter. It has no fixed shape or volume, meaning it can be compressed and squeezed, and it flows.
Liquid: A state of matter involving randomly organised particles that are fairly closely packed, but less densely than in a solid. It has a fixed volume but no fixed shape; it will take the shape of its container. The particles are able to move and flow over each other.
Melting: The change of state from solid to liquid. Due to an increase in thermal energy, the kinetic energy of the particles increases, making the bonds or intermolecular forces break and allowing the particles to be freed from their fixed positions and flow over one another.
Solid: A state of matter in which the particles are closely and regularly packed and vibrate about a fixed point. It does not flow and has a fixed shape and volume, and it is the most dense state of matter.
Sublimation: The change of state from solid to gas, skipping the liquid phase. (Deposition is the same but changing state the opposite direction, from gas to solid). Examples include carbon dioxide, which sublimes into dry ice, or when the sun heats a field of snow. Sublimation occurs when the total pressure of the atmosphere is less than the vapor pressure of the compound, and the temperature has not yet reached the substance's melting point. The particles spread out quickly to change state from solid to gas quickly.
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Section 3 a) Specification
3.1 explain the terms homologous series, hydrocarbon, saturated, unsaturated, general formula and isomerism. A homologous series is a grou...
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The group 7 elements, also known as halogens, are F, fluorine, Cl, chlorine, Br, bromine, I, iodine, and At, astatine. They all have antimic... -
Metals can be placed in an order of most to least reactive, called the reactivity series. This can be remembered using an acronym: Plea... -
Particles of a substance can be present in different physical states, the states of matter. They are solid, liquid and gas, and increasing ...
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