states of matter and separating substances Flashcards
what ae particles like in substances in the solid, liquid and gas states?
solid- close together, regular patter, vibrate round fixed position, least stored energy
liquid- close together, random, move around eachother
gas- far apart, random, fast in all directions, most stored energy
what changes happen to particles during the different changes of state?
energy is transferred to or from particles, the arrangement of particles changes, movement of particles changes
how do you decide what state a substance will be in at a given temperature?
a substance is solid below its melting point, gas above its boiling point and liquid between melting and boiling points.
what is the difference between a pure substance and a mixture?
pure substance contains only one element or compound, mixtures contain different elements and/or compounds
what happens to its particles when a solid melts?
energy is transferred to particles
how do melting points allow you to spot the difference between pure substances and mixtures?
how can filtration be used to separate mixtures?
purifying a liquid/solution by removing impurities from it
separating the solid you want from the liquid its mixed with
how can crystallisation be used to separate mixtures?
heating solution to remove solvent to produce saturated solution, saturated solution cools down, crystals form in solution, crystals separated from liquid and dried
what are the hazards and risks when separating mixtures by these methods
how can chromatography be used to seperate mixtures?
substances with stronger attractions to stationary phase stay near the bottom and substances with stronger attractions to mobile move towards the top
what are the differences between mixtures and pure substances on a chromatogram?
a pure substance will produce only one spot
how do you calculate an Rf value?
Rf = distance travelled by spot/distance travelled by solvent
what is distillation?
separating liquids from mixtures
how do simple and fractional distillation differ?
simple: separates solvent from solution, solute has higher boiling point than solvent
fractional: separates liquid from mixture of miscible liquids, liquids in mixture have different boiling points
how would you reduce risks when carrying out a distilation method?
safety goggles,
