Solids, Liquids and Gases

Pregunta	Respuesta
Solids have particles that....? Solids have....?	are close together, vibrate along fixed means. Fixed shape, fixed volume and cannot flow.
Liquids have particles that....? Liquids have....?	are still close together, slide past each other. Fixed volume, take shape of the container. Can flow
Gases have particles that....? Gases have....?	are far apart, move randomly everywhere. No fixed shape and volume. Can flow.
Particles can either be...?	Ions Molecules Atoms
What is an ion?	An electronically charged atom.
What is the difference between an atom and a molecule?	An atom is the smallest particle that cannot be put into simpler forms chemically while a molecule is two or more atoms chemically combined.
Why does the melting and boiling points of a PURE substance always occur at a constant temperature?	Because the energy (got from either the heat or cold) is used to break the forces of attraction instead of raising the temperature.
Why does diffusion not take place in solids but in liquids and gases only? What diffuses faster, gases or liquids?	Particles in liquids and gases move freely while particles in solids cannot move. Gases diffuse faster because the particles are more free and move faster.
What diffuses faster, ammonia solution (NH3) or HCL and why?	Ammonia solution diffuses faster because it has a lower molecular mass than HCL.
What is the diffusion rate?	Diffusion rate is inversely proportional to the square root of its relative molecular mass.
What 5 methods are used to separate mixtures and when are they used?	Filtration - separating an insoulble solid from a solution Simple distillation - separating a liquid from non volatile impurities (soluble solid) Fractional distillation - separating a mixture of miscible liquids of different boiling points Chromatography - separating different components of a mixture by using their different speeds of movement Solvent extraction
What is residue?	The remnant after an experiment. (filtration, distillation)
What is the difference between simple and fractional distillation?	Simple distillation separates a soluble solid from a solution by evaporating the liquid leaving the solid behind and then condensing the liquid; fractional distillation separates a liquid from a solution of two or more miscible liquids.
Describe fractional distillation using a mixture of ethanol and water.	The solution is boiled. At 90 degrees, as told by the thermometer, ethanol boils. At this temperature water is a liquid and ethanol, a gas. The ethanol vapor travels up the fractionating column and is condensed and collected as a distillate while the water is left behind as a residue.
Describe chromatography briefly.	Chromatography is the separation of different components from a mixture by using their different speeds of movements over a medium (filter paper or chromatography paper). Capillary attraction carries the components upwards.
The speed at which the components, during chromatography, depends on...	The molecular mass: the lower the faster the component The attraction towards the component: the stronger the faster the component
What is the retention factor and how can it be used?	distance traveled by component divided by the distance traveled by the solvent front. Retention factors are compared with known materials to identify components of the mixture.
What is a pure substance and what is its importance?	Contains only one kind of substance and is used in medicine and the food industry. Any impurity can be fatal.
How is purity assessed?	By determining the boiling and melting point. Impurities increase the boiling point and lower the melting point.

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	Creado por Pranathi Poojary hace alrededor de 8 años