chapter 1 - particulate nature of matter Flashcards
what are elements
substances made from one kind of atom
what are compounds
made from 2 or more elements chemically bonded
how are compounds formed
atoms combine together in fixed ratios that will give them full outer shells of electrons, producing compounds
what is a mixture
when the components of a mixture are not chemically bonded together, so they retain their individual properties.
why will substances burn in the air
the oxygen present in air supports combustion
what is a homogeneous mixture
has uniform composition and same properties throughout
what is a heterogeneous mixture
non-uniform composition, so its properties are not the same throughout
what type of mixtures are air and bronze
homogeneous
what type of mixtures are concrete and orange juice
heterogeneous
what are solvation and filtration used to separate
an undissolved solid from a mixture of solid and a liquid
steps for filtration
-filter paper placed in filter funnel above a beaker
-mixture of insoluble solid and liquid poured into filter funnel
-filter paper only allows small liquid particles to pass through in the filtrate
-solid particles too large to pass through so stay behind-residue
what is crystallisation used to separate
a dissolved solid from a solution when the solid is more soluble in hot solvent than cold
steps of crystallisation
lowly using gentle heating or just leaving a saturated solution to evaporate so that larger crystals are formed which are easier to separate
what is recrystallisation used for
to purify impure solids
what is simple distillation used to separate
to separate a liquid and soluble solid from a solution (e.g. water from a solution of saltwater) or a pure liquid from a mixture of liquids
what is fractional distillation used to separate
to separate 2 or more liquids that are miscible with one another (e.g. ethanol and water from a mixture of the two)
steps
solution is heated to the temp of the substance with the lowest bp, this rises and evaporates first, vapour passes through condenser - liquid and collect in beaker
what is paper chromatography used to separate
separate substances that have different solubilities in a given solvent (e.g. different coloured inks that have been mixed to make black ink)
if there are flammable liquids present, what is safer to use?
an electric heater
how does solvent travel up paper in chromatography
capillary action- bring coloured substances with it
name of state change from solid to gas
sublimation
name of state change from gas to solid
deposition
how do you convert kelvins to degree celcius
temperature in K = Temperature in °C + 273
