topic 9

Question 1

What colour flame is formed when the compound is put in a flame: Lithium, Sodium, Potassium, Calcium, Copper

Answer 1

lithium-red sodium-yellow potassium-lilac

calcium-orangy red copper-blueish green

Question 2

How do you carry out the flame test

Answer 2

1. Clean nichrome wire loop in hydrochloric acid and rinse with distilled water.
2. Then dip into sample of the metal compound and hold over clear blue part of the flame (hottest part) and record result.

Question 3

what happens when a insoluble metal hydroxide is formed?

Answer 3

it precipitates out of the soloution

Question 4

what is the colour of the precipitate: Aluminium, calcium, copper(II), Iron(II), Iron(III)

Answer 4

Aluminium- white at first the redissolves in to colourless
Calcium-white copper(II)-blue iron(II)-green
iron(III)-brown

Question 5

test for ammonia ions/gas

Answer 5

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

Question 6

Test for halide ions (chloride, bromide, iodide)

Answer 6

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)

Question 7

test for carbonate iona

Answer 7

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

Question 8

sulfate ion test

Answer 8

add dilute hydrochloric acid (stops any other precipitate reactions) add barium chloride solution white precipitate should form

Question 9

what is flame photometry

Answer 9

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

Question 10

how to work out concentration from intensity using calibration curve

Answer 10

find intensity on y axis, find the point on the y axis and then go down to see the x axis

Question 11

how can use flame photometry for mixtures

Answer 11

compare the line spectrum of your mix of ions to a reference spectra of a know ion

Question 12

advantages of using machine in chemistry (instrumental analysis)

Answer 12

very sensitive-detect tiniest amount of substances
very fast-can be automated
very accurate- no human error

Question 13

what are nanoparticles

Answer 13

really tiny particles about 1-100 nanometers across containing a few hundred atoms, and have very different properties from the bulk

Question 14

what do fullerenes have

Answer 14

nanotubes, tiny hollow carbon tubes, with convalent bonds making them very strong

Question 15

surface area to volume ratio formula

Answer 15

surface area / volume (as a particle decreases in size surface area increases)

Question 16

what gives nanoparticles different properties

Answer 16

the high surface area to volume ratio as more particles can interact

Question 17

why are nanoparticles good for catalysts

Answer 17

high sa:v ratio means bigger surface to react with, more collisions, faster rate

Question 18

why are nanoparticles good for sunscreen

Answer 18

better protection,no white marks

Question 19

why are nanoparticles good for medicine

Answer 19

nanomedicine, idea that fullerenes are absorbed more easily by body, so could deliver drugs right to the cell

Question 20

why are nanoparticles good for lubricant coating

Answer 20

through the use of fullerenes for artificial joints and gears

Question 21

why are nanoparticles good for computer chips

Answer 21

they conduct electricity so can be used in electrical circut

Question 22

why are nanoparticles good for sports equipment

Answer 22

they are added to plastic equipment like tennis racket, to add strength and durability without adding much mass

Question 23

why are nanoparticles good for surgical masks

Answer 23

silver nanoparticles added to polymer fibres to mask and wound dressing, giving them antibacterial properties

Question 24

why are people worried about nanoparticles

Answer 24

they believe they have been made avaliable without investigation on harmful effects on human health

Question 25

high-density poly(ethene) use

Answer 25

strong rigid polymer used for water pipes

Question 26

low-density poly(ethene) use

Answer 26

light stretchy, used for plastic bags and squeezy bottle

Question 27

poly(styrene)foam use

Answer 27

used in packaging and a thermal insulator

Question 28

melamine resin and poly(propene)

Answer 28

heat resistant used to make plastic kettles

Question 29

what is clay

Answer 29

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

Question 30

glass

Answer 30

transparent and strong, moulded when hot, brittle when thin, majority soda lime-glass, made by heating and cooling sand, limestone, sodium carbonate

Question 31

what are composites

Answer 31

made of one material (the reinforcement) embedded in another (the matrix/binder)

Question 32

carbon fibre composite?

Answer 32

made by using carbon atoms bonded

Question 33

properties of polymers

Answer 33

flexible, easily moulded, cheap, less dense, can degrade/break down, thermal and electrical insulator

Question 34

properties of metals

Answer 34

conductors of heat and electricity, malleable, can be corrosion resistant, less brittle will deform not shatter

Question 35

properties of composites

Answer 35

properties depend on the matrix/binder and the reinforcement, can be expensive

Question 36

properties of cermaics

Answer 36

insulators of heat and electricity, brittle, stiff, strong, hard wearing, don’t degrade of corrode