topic 9 Flashcards
What colour flame is formed when the compound is put in a flame: Lithium, Sodium, Potassium, Calcium, Copper
lithium-red sodium-yellow potassium-lilac
calcium-orangy red copper-blueish green
How do you carry out the flame test
- Clean nichrome wire loop in hydrochloric acid and rinse with distilled water.
- Then dip into sample of the metal compound and hold over clear blue part of the flame (hottest part) and record result.
what happens when a insoluble metal hydroxide is formed?
it precipitates out of the soloution
what is the colour of the precipitate: Aluminium, calcium, copper(II), Iron(II), Iron(III)
Aluminium- white at first the redissolves in to colourless
Calcium-white copper(II)-blue iron(II)-green
iron(III)-brown
test for ammonia ions/gas
add sodium hydroxide to mystery solution, if gas is given off, hold damp red litmus paper over it, if ammonia ions are present it’ll turn blue, it does have a distinctive smell, but ammonia is toxic so it is dangerous to inhale it
Test for halide ions (chloride, bromide, iodide)
add dilute nitric acid to solution then few drops of silver nitrate solution: chloride-white precipitate (silver chloride) bromide-cream precipitate (silver bromide)
iodide-yellow precipitate (silver iodide)
test for carbonate iona
add acid, it should fizz and give off bubbles of carbon dioxide, run gas through lime water to check if it is CO2 should turn milky
sulfate ion test
add dilute hydrochloric acid (stops any other precipitate reactions) add barium chloride solution white precipitate should form
what is flame photometry
instrumental method, allows you to identify ions in a dilute solution, different ion different line spectrum different lines in different places, intensity of measured wavelength indicates concentration
how to work out concentration from intensity using calibration curve
find intensity on y axis, find the point on the y axis and then go down to see the x axis
how can use flame photometry for mixtures
compare the line spectrum of your mix of ions to a reference spectra of a know ion
advantages of using machine in chemistry (instrumental analysis)
very sensitive-detect tiniest amount of substances
very fast-can be automated
very accurate- no human error
what are nanoparticles
really tiny particles about 1-100 nanometers across containing a few hundred atoms, and have very different properties from the bulk
what do fullerenes have
nanotubes, tiny hollow carbon tubes, with convalent bonds making them very strong
surface area to volume ratio formula
surface area / volume (as a particle decreases in size surface area increases)
what gives nanoparticles different properties
the high surface area to volume ratio as more particles can interact
why are nanoparticles good for catalysts
high sa:v ratio means bigger surface to react with, more collisions, faster rate
why are nanoparticles good for sunscreen
better protection,no white marks
why are nanoparticles good for medicine
nanomedicine, idea that fullerenes are absorbed more easily by body, so could deliver drugs right to the cell
why are nanoparticles good for lubricant coating
through the use of fullerenes for artificial joints and gears
why are nanoparticles good for computer chips
they conduct electricity so can be used in electrical circut
why are nanoparticles good for sports equipment
they are added to plastic equipment like tennis racket, to add strength and durability without adding much mass
why are nanoparticles good for surgical masks
silver nanoparticles added to polymer fibres to mask and wound dressing, giving them antibacterial properties
why are people worried about nanoparticles
they believe they have been made avaliable without investigation on harmful effects on human health
high-density poly(ethene) use
strong rigid polymer used for water pipes
low-density poly(ethene) use
light stretchy, used for plastic bags and squeezy bottle
poly(styrene)foam use
used in packaging and a thermal insulator
melamine resin and poly(propene)
heat resistant used to make plastic kettles
what is clay
weathered decomposed rock, soft when it is dug up making it easy to mould, can be hardened by firing it at high temperatures, good for building, can withstand many more bricks ontop
glass
transparent and strong, moulded when hot, brittle when thin, majority soda lime-glass, made by heating and cooling sand, limestone, sodium carbonate
what are composites
made of one material (the reinforcement) embedded in another (the matrix/binder)
carbon fibre composite?
made by using carbon atoms bonded
properties of polymers
flexible, easily moulded, cheap, less dense, can degrade/break down, thermal and electrical insulator
properties of metals
conductors of heat and electricity, malleable, can be corrosion resistant, less brittle will deform not shatter
properties of composites
properties depend on the matrix/binder and the reinforcement, can be expensive
properties of cermaics
insulators of heat and electricity, brittle, stiff, strong, hard wearing, don’t degrade of corrode
