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C4. Predicting and identifying reactions and products - Coggle Diagram
C4. Predicting and identifying reactions and products
Predicting chemical reactions
Group 1. ALKALI METALS
Far left of periodic table
React with water to form Alkali solutions
Shiny when freshly cut. Good electric conductors
Trends.
:green_cross: going down periodic table increases density.
:green_cross: melting point decreases down table
:green_cross: reactivity increases going down table (electron less attracted to nucleus)
Turn dull when exposed to air or water - oxidise
All group 1 (and group 2) elements end with ium.
Alkali Metal + Water -> Metal Hydroxide + Hydrogen
Group 7
Diatomic
Reaction strength decreases as you go down table
(more violent to gain electron easily)
Iodine
Shiny grey at room temp
sublimes to purple vapour
4.93 G/CM3 at room temp
Chlorine.
Green gas at room temp
0.00290 g/cm3 at room temp
Fluorine
Pale yellow gas at room temp
0.000155 g/cm3 room temp
Bromine
Orange-brown Liquid at room temp
3.1 g/cm3 at room temp
Less reactive as you go down periodic table
React vigorously with group 1 metals to produce salts
Grp1 + Grp7 -> Salt
Group 0
:green_cross:
NOBEL GASES
:green_cross:VERY UNREACTIVE
:green_cross:FULL OUTER SHELL
:green_cross:MONATOMIC
:green_cross:LOW DENSITY
Going down table...
Increases boiling point
Increases attractive force between atoms
Increased density
Halogen displacement reactions
HALOGENS can react with HALODIDES (compound containing grp 7 element + 1 other element) in solutions IF the HALOGEN is MORE reactive than the HALIDIDE ION
:green_cross: CL2 (g) + 2NaBR (aq) -> 2NaCL (aq) + Br2 (aq)
Chlorine > Bromine from bromides > Iodine from iodides
HALF EQUATIONS REDOX (Oxidation = loss, reduction is gain)
Cl2 + 2e- -> 2Cl- (Reduction)
2Br- -> Br2 + 2e- (Oxidation)
Transition metals
Between Grp 2+3
Shiny when freshly cut
Good heat + electrical conductors
Strong
Malleable
Compared to alkaline metals
:green_cross:Stronger
:green_cross:Harder
:green_cross:Higher density
:green_cross:Higher melting points (except mercury)
CHEMICAL TRENDS
Less reactive than Alkalines
Reacts slowly with water and oxygen
Gold, Platinum + iridium completely unreactive
Can form more than one type of ion (Iron (II) Fe2+, Iron (III) Fe3+)
Good catalysts (Platinum, rhodium and palladium catalytic converters for cars)
Reactivity of elements
Metals form positive ions in reactions
Metal can react with water or dilute acids if more reactive than Hydrogen
Metals react with
Water to form Metal Hydroxide and Hydrogen
Acid to form a salt and Hydrogen
REACTIVITY SERIES
1.Potassium
Sodium
Calcium
Magnesium
Aluminium
Carbon
Zinc
Iron
Tin
Lead
Hydrogen
Copper
Silver
Gold
Platinum
Metal displacement reactions
More reactive metal can displace less reactive one from solution.
EG. Cu (s) + 2AgNO3 (aq) -> Cu(NO3)2 (aq) + 2Ag (s)
Half equations
Cu (s) -> Cu2+ (aq) + 2e-
Ag+ (aq) + e- -> Ag (s)
Predictions
Grp 0 do not react
Reactive non metals can form covalents with one another
Metals can form Ionics with reactive non metals
Grp 1+2 more reactive than transitions
Grp 1+2 increase reactivity down group
Grp 7 less reactive down table
Identifying products of chemical reactions
Detecting gases
:green_cross:CO2 - Limewater (calcium hydroxide solution) turns cloudy white when exposed. Calcium Hydroxide reacts with CO2 to form water and white precipitate of CaCO3
:green_cross:Chlorine - Litmus paper. Dampen in tap water, then hold near container. Will turn red then white if Chlorine present
:green_cross:Hydrogen - Squeaky pop splint test
:green_cross:Oxygen - relights splint
Can smell substances but must be careful you aren't inhaling poisonous gases
Detecting cations
Lithium:green_cross:Li+:green_cross:Red
Sodium:green_cross:Na+:green_cross:Yellow
Potassium:green_cross:k+:green_cross:Lilac
Calcium:green_cross:Ca2+:green_cross:Orange-red
Copper:green_cross:Cu2+:green_cross:Green-blue
Detecting anions
Instrumental methods of analysis