Reactions
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In chemistry, a reaction reaction is a process that leads to the transformation of one set of chemical substances to another.
Important Reactions to Know
Alkali Metals
The following examples will use Potassium (K) to represent the reactions that elements in group 1 undergo
Reactions with oxygen
(excess oxygen) 2K(s) + O2(g)--> K2O2
(limited oxygen) 2K(s) + 1/2 O2(g)--> K2O
Reactions with water
2K(s) + 2H2O(l) ---> 2KOH(aq) +H2(g)
K2O(s) + H2O(l) ---> 2KOH (aq)
K2O2(s) + 2H2O(l) ---> 2KOH(aq) + H2O2(aq)
Reactions with Halogens
2K(s) + Br2(g) ---> 2KCl(s) (Other alkali metals and halogens react the same way)
Alkaline Earth Metals
The following examples will use Magnesium (Mg) to represent the reactions that elements in group 2 undergo
Reactions with Oxygen
Mg(s) + 1/2 O2(g) ---> MgO(s)
Reactions with Water
(Magnesium is coated with MgO(s) which is poorly soluble in water at room temperature; therefore magnesium does not react vigorously with water, unless the coating is dissolved in boiling water or hydrochloric acid)
Mg(s) + 2H2O(l,g) ---> Mg(OH)2(aq)+ H2(g)
Reactions with Halogens
Mg(s) +Cl2(g) ---> MgCl2(s) (other alkaline earth metals and halogens react in the same way)
Group 13 Elements
Al(l) + 3 O2 (g) --> Al2O3 (g)
2 Al (s) + Fe2O3 (s) --> Al2O3 (s) + 2Fe(l)
2 Al (s) + 3 Cl2 (g) ---> 2 AlCl3 (s)
The aluminum(III) ion in aqueous solution is surrounded by the oxygen atoms of 6 water molecules.
Group 14 Elements-Silicon
Si(s) + H2O(l,g) ---> NO REACTION (silicon oxide coating prevents reaction)
Si(s) + O2(g) ---> NO REACTION
Above 1000 degrees Celsius: Si(s) + O2(g) ----> SiO2(s)
At 300 degrees Celsius: Si(s) + 2 Cl2(g) ----> SiCl4(l)
Group 15 Elements- Phosphorus
Reactions with Oxygen (only white phosphorus)
P4(s) + 3 O2(g) ---> P4O6(s) (limited Oxygen)
P4(s) + 5 O2(g) ---> P4O10(s) (excess Oxygen)
P4(s) + 6 Cl2 (g) ---> 4 PCl3 (l) (limited Chlorine)
This reaction produces a colourless liquid
P4(s) + 10Cl2 (g) ---> 4 PCl5 (s) (excess Chlorine) This reaction produces a white solid
P4O6 (s) + 6 H2O (l) ---> 4 H3PO3 (aq) (phosphorous acid)
P4O10 (s) + 6 H2O (l) ---> 4 H3PO4 (aq) (phosphoric acid)
Group 16 Elements- Sulfur
Claus Process: 2 H2S(g) + 3 O2(g) ---> 2 SO2(g) + 2 H2O(g) ---- and ---- 2 H2S(g) + SO2(g) ---> 3 S(l) + 2 H2O(g) at 300 degrees Celsius
S(s)+2 O2(g) ---> SO2(g)
2 SO2(g) + O2 (g) ---> 2 SO3 (g)
SO3(g) + H2O ---> H2SO4 (aq) (sulfuric acid)
SO2 (g) + H2O ---> H2SO3 (aq) (sulfurous acid)
Group 17 Elements
Cl2(g) + 2NaOH (aq) ---> NaOCl(aq) + NaCl(aq) + H2O(l)
Group 18 Elements
Bartlett experiment: Xenon compound
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