C4 Tests Flashcards
Fluorine chlorine bromine iodine
Halogen exist at room temp
Fluorine is pale yellow gas
Chlorine is a green gas
Bromine orange brown liquid that vaporises easily
Iodine is purple black crystaline solid that sublimes to give a purple vapour
Group 1 alkali
Why react more lower you go
- have same chemical properties because all have on electron outside
- thus easier it is to lose this electron, more reactive they are
- Lowe thou go it gets easier as they have more shells, meaning distance between nucleus and outer electron is more (atom gets larger) , so electron less strongly attached to nucleus as force of attraction weakens and LESS energy needed to remove it
- electron more readily lost / eaisky lost
Trends of group 1 metal
3
Sodium density?
(Higher then expected)
Properties of group 1
4
Go down = - more react - density increase (sodium bit more ) - melting/boiling decrease
2)
- low boiling compared it other metal
- soft (easy cut and shiny )
- low density
- other typical properties of metal like electrocuted
What will relation fo alkali and water do
Universal,?
Produce hydroxide and hydrogen
Hydgrien msy burn
Hydroxide turns universal indicator blue as ALKALINE SOLUTION
Group 1 gets more violent how?
Lithium
Sodium
Potassium
React with water
Lithium fizzes steadily and slowly reacts
Sodium melts to form silvery ball, quickly react (melt)
Potassium immediately ignited, Bruns lilac
Trends of group 7 halides
3
Properties
2
Go down
- melting boiling increase
- density increas like group 1
- reactivity decrease
2)
- typical of non metals: brittle and not conduct electricity
- diatomic covalent
Why group 7 lose reactivity les more down you go
Why called halogens, what halos
Group 7 all haveb7 electrons in outer shell
- easier it is to gain extra electron the more reactive- l
- lower down you go the bigger atom gets because more shells thus strength of starvation between nucleus snd electron gets weaker, and so harder it attracts an electron to fill shell= less relative
Halogens caked halogen becaus they react with a metal to form a salt , particularly the alkali.
Halos means salt
Halogen displacement , also what other reacting ARE THEY
How can you carry out practical to determine reactivity of halogens
What halos
Higher halogens displace lower reactive halogen from halide.
2) REDOX
3) - halide compound with group 7 and other metal
Use them to find order of reactivity for them
1) spotting tile where reacting chlorine water with all three halide (potassium chloride, bromide iodide) . Note observations and repeat for other solutions of BROMINE water and IODINE water
2) in table you see chlorine displace iodine and bromine, bromine displace iodine snd iodine nothing = shows you reactivity series
Halide is compound
Summary
1) spotting tile , put halide salt solution and then react halide with halogen solution.
2) colour change= displacement happened, record snd repeat with others
Potassium everything X halogen
Trends in noble gas?
3
Properties of noble
3 (mono)
Go down =
- attractive force stronger
- thus boiling increase
- density increase
2)
- monosyomic (one atom),
- weak forces of attraction between them which easily ivercome so LOW BOILING POINT (gases have them anyways)
- gas have low density so low density (same mass less volume )
Why noble gas not reactive
How to predict next temp
Why not inert
Full outer shell do no tendency to lose or gain electron (so not flammable too)
Find gaps and then average gap and then add
Still can react
Transition metals
Physical vs Akamai
Chemical (3)
What are they good
Have more than one ion and less reactive than other metals
Typical = shiny cut, conduct electricity, malleable, string, dense
Compared without alkali = more dense + boiling , hard , less reactive
2) Iron reacts with water to make rust (iron three oxide)
Gold platinum don’t
- colourful compounds Ionic
3) GOOD CATALYSTS
Elements trend summary?
All alkali 7 and 8 density + boiling increase, but alkali melting and boiling decrease lower you go
Reactivity series tests
- what can a metal rests with water and acid only when?
What is a displacement reaction also
How to carry out displacement (2 ways)
1) can react with water= OH and acid= salt if the metal more reactive then HYDROGEN
2) can displace a lower reactive metal , whip is redox
1) The more hydrogen it releases, the more reactive it is/ faster bubbles more reactive
2) Put metal and acid, observe rate of bubbling
3) If not react Warm it but don’t boil.
4) if do with water use steam for less reactive
Use spotting tile table to find out order if reactivity, here put metal one side vs metal aqueous solution observe changes
Hydrogen and oxygen test?
Remember for hydrogen it will…
Hydrogen, place lighted splinter near mouth if contained and it will IGNITE with squeaky pop
Oxygen, place glowing solid near mouth and should RELIGHT
Chlorine gas test
Why must use water to dampen?
1) dampen blue litmus paper with water
2) hold above the container of chlorine gas
3) if gas then it will go from blue to red then white because bleaching
Must dampen because chlorine dissolves in water to form acidic solution which ten makes blue litmus paper red. It also bleached which is why it goes white
How to smell substance in lab?
Why we hold it away from us?
1) Container away from nose breathe enough air to almost fill lungs
2) hold container a few cm from your nose and wad any smell towards you. Take csutitous sniff
Holding away means not a lot goes into to you and that’s if it escapes it won’t go to your nose .
Flames test
Why Nichrome wire
What are the colours
1) clean a njchrime loop by dipping it in HCL a few times then water. To check if clean hold it above flames and see if none is produced
2) if nine, the you can dip the wire in a sample, and then hold it near mouth of flame. Colour produce, and then re CLEAN
liar lithium red
Soy. Sodium yellow
Poll potassium lilac
Cogb copper green blue
Caor claicum orange red
Hyrodoixde precipate tests
What are the colours
Distinguish between zinc and calcium
Most metal hydroxides not soluble in water produce predicates, so use this for test
1) add a few drops of sodium hydroxide to a solution containing metal ions
2) see colour of them
1) copper blue
2) iron 11 is green
Iron 3 is orange brown
Calcium and zinc bith white,
Dissiove in excess copper sulfate, if it dissolves it is zinc , if stays predicates then calcium
SUKFSTE
Why use acid ?
Barium ions will react with sulfate ions to form insoluble barium sulfate . (We add HCL because barium sulfate
1) acidity it first by adding a few drops of HCL
2) then add a few drops of barium chloride solution
4) if sulfate it become white precipitate
Carbonate ions?
1) add a few drops of HCL to Solution with carbonate, if there then carbon dioxide produced , do limewater rest to make sure
2H+ + Co3-2 -> co2 + h20
Acid h+ ions react with carbonate to form carbin dioxide , bubbles and limewater
Halide ion test?
Why add nitric acid first? (Important)
1) acidity with a few drops NITRIC acid
2) add silver nitrate to solution containing halide
3) milk cream butter
Chlorine, bromine iodine
Gets rid of any carbonate ions (or else they form white precipate with silver confusing result ) with , and csn’t use hydrochloride acid because then chlorine would be there and you wouldn’t know where it came from
Mass spectrometry
What are advantages of instrumental method of analysis (machine instead of human)
1 ) Instruments better more accurate (can be calibrated with internationally accepted standards) much more bigger than human
2) Sensitive (less substance is needed to detect
3) speed happen quick and happen all the time (can even be automated)
Spectrogram (is a graph of result)
What is it used for (two things)
How are molecules analysed ?
mass spectrometer measure the masses of atoms and molecules. Can analyse relative amounts of different iostopes of an element
2) good for molecules analysis. molecules ionised into molecular ions by machine , which break up and form fragments that the machine can SEPARATE AND DETECT
- Each peak represents a fragmented particle
- peak on the far right represents the molecular ion, and then MASS TO CHARGE RATIO OF THIS IS = TO THE RFM of the entire molecule
Carbon dioxide test
Limewater?
What happens (what formed)
Carbon dioxide=
- limewater (calcium hydroxide) turns cloudy white when co2 bubbled through it
- forms water and a WHITE PRECIPATE OF CALCIUM CARBONATE
