Flashcards
Solids, Liquids and Gases
Cards in this deck (19)
- 1Solids have particles that....? Solids have....?are close together, vibrate along fixed means.
Fixed shape, fixed volume and cannot flow. - 2Liquids have particles that....? Liquids have....?are still close together, slide past each other.
Fixed volume, take shape of the container. Can flow - 3Gases have particles that....? Gases have....?are far apart, move randomly everywhere.
No fixed shape and volume. Can flow. - 4Particles can either be...?Ions
Molecules
Atoms - 5What is an ion?An electronically charged atom.
- 6What 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.
- 7Why 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.
- 8Why 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.
- 9What diffuses faster, ammonia solution (NH3) or HCL and why?Ammonia solution diffuses faster because it has a lower molecular mass than HCL.
- 10What is the diffusion rate?Diffusion rate is inversely proportional to the square root of its relative molecular mass.
- 11What 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 - 12What is residue?The remnant after an experiment. (filtration, distillation)
- 13What 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.
- 14Describe 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.
- 15Describe 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.
- 16The 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 - 17What 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. - 18What 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.
- 19How is purity assessed?By determining the boiling and melting point. Impurities increase the boiling point and lower the melting point.