Section 3 - Inorganic Chemistry x_x Flashcards
group one metals
group one metals all react in a similar way with water
(Li, Na, K react vigorously and produce metal hydroxide alkaline solution and hydrogen -fizzing-)
react with o2
- lithuim forms lithium oxide (li2o)
- sodium forms sodium oxide (Na2O) and sodium peroxide (Na2O2)
- potasium forms potasium peroxide (K2O2) and potasium superperoxide (KO2)
group one properties
become more reactive down group (loose electrons more easlily as there is more space to nucleus)
halogens properties
as atomic number increases (go down) they are darker and have a higher boiling point
at room temp:
- chlorine is a poisonous green gas
- bromine is a poisonous red-brown liquid which gives off orange vapour at room temp
- iodine is a drak grey crystaline solid that gives of purple vapour when heated
- higher up metal in group 7 is more reactive
transfer of electrons in a displacement reaction
a loss of electrons (oxidation) and gain of electons (reduction ) happen simultaneously (element displaced is oxidised and element taking its place is reduced)
oxidising agent accepts electrons and gets reduced
reducing agent gives away electons and gets oxidised
this is a redox reaction
displacement in halogens
???
gases in atmosphere
78% nitrogen
21% oxygen
nearly 1% noble gases
0.04% CO2
investigate proportion of oxygen in atmosphere
1) first soak iron wool in aceietic acid (calayses reaction), then push wool into measuring cylinder in beaker of water
2) record starting position of water on scale of measuring cylinder (starting volume of air)
3) over time it will rise becasue the iron reacts with oxygen to make iron oxide and water rises to fill space oxygen took up
4) leave for week and then record final position of water
phosphorus to determine percentage of o2 in air
place phosphorus in tube and attach a syringe at either end, one of them filled with air the other empty
heat pjhosphorus and use syringes to pass air over it
phosphus will react with o2 to make ohosphus oxide, so air in syringes will decrease
measure starting and final volumes of air with syringes scales and calculate oxygen percentage (s - f /s )
magnesium burns in air
- bright white flame
- white powder formed (magnesium oxide)
- magensium oxide skightly alkaline dissolved in water
hydrogen burns in air
- burns easily in oxygen, in fact can be explosive
- almost invisible pale blue flame
- product = water (as water vapour)
- used to test for hydrogen gas, giving squeaky popu
sulfur burns in air
- pale blue flame
- produces sulfur dioxide
- acidic when dissolved in water
thermal decomposition of metal carbonates
produces co2 and a metal oxide
thermal decomposition = subsyance breaks down into simpler substances when heated
copper(II) carbonate is a green powder that will easily decompose to form carbon dioxide and copper(II) oxide when heated
you can prove this in an experiment where you heat it and collect produced gas with test tube, which you can test to see if its co2
CuCO3 -> CuO - CO2
carbon diozide as a greenhouse gas
greenhouse gases act as an insulating layer and absorb heat that would be radiated out into space
humans make there be more co2
- deforestation
- burn fossil fuels
co2 leads to climate change
increase in co2 has casued avg temp to rise and affected weather patterns
(page 40 add info)
metals react with acids
metal + acid = salt + hydrogen
you can use this to work out how reactive a metal is (more reactive = faster reaction)
- set up 3 boiling b¡tubes and fill with equal volumes of dilute hydrochloric acid or dilute sufluric acid
- place pieces of magenesium zinc and iron in separate test tubes (size and shape between them is the same)
- speed of reaction can be indicated by rate at which bubbles are given off
- hydorgen confirmend by burning splint test (squeaky pop)
magnesium most reactive
zinc middle
iron least reactive
reactivity series
potassium
sodium
lithium
calcium
magnesium
aluminium
zinc
iron
copper
silver
gold
displacement
- more reactive takes place of least reactive, because it bonds more stringly.
- displacement is redox reactions
- if a reaction occurs there is change in temperature(more reactive = more temp)
rust
iron + oxygen + water = hydrated iron (iii) oxide (rust)
- rusting happens when iron is in contact with both water and oxygen
- oxidation reaction where iorn gains electrons to form iron (III) oxide
- water becomes loosesly bonded forming hydrated iron(III) oxide - rust
preventing rusting (barrier)
barrier methods
- paint / coat with plastic - not in direct contact with iron
- oiling/ greeasing - ideal for moving oarts like bike chains
preventing rusting (sacrificial)
(place a more reactive metal with the iron, therefore the water and oxygen react with this instead)
zinc
- its more reactive, so it will be oxidised instead
- coaying of zinc can be sprayed - galvanising
- bigblocks of zinc can be bolted to iron
oxidation
gain of oxygen
reduction
loss of oxygen
universal indicator
red - yellow - acidic
green neutral
blue -purple -alkaline
litmus paper
red acidic
purple neutral
blue alkaline
phenolphthalien
clolourless acidic
purple alkaline
methyl organe indicatior
red acidic
yellow alkaline
acid
source of hydorgen ions, proton donors
base
substance that can neutralise an acid, proton acceptors
alkalise - soluble bases
alkali - source of OH⁻ ions with ph greater than 7
neutralisation
reaction between acid and base
H + OH = H20
when are salts formed
when acids react with bases
acid + base = salyt + water
type of salt depends on acid
HCl = chloride salts
sulfuric acid = sulfate salts
nitric acid = nitrate salts
different bases:
acid + metal oxide = salt + water
acid + metal hydorxide = salt + water
acid + ammnia = ammonium salt
acid + metal carbonate = salt + water + co2
acid + metal = salt + hydrogen
rules of solubility
salt can be a precitpitate (insoluble) or in solution (soluble)
sodium potassium and ammonium salts = soluble
nitrates = soluble
chlorides = soluble (except silver and lead chloride)
sulfates = soluble (except lead, barrium and calcium sulfate)
carbonates = insoluble ( except sodium potassium and ammoniums)
hydroxides = insoluble (except sodium potasium and calcium)
make a soluble salt
acid and insoluble base
