(a) List any three observations which determine that a chemical reaction has taken place . Also list three informations that cannot be obtained about a chemical reaction, merely by its chemical equation.
(b) Balance the following chemical equations.
(i) `Fe+H_(2)OrarrFe_(3)O_(4)+H_(2)`
(ii) `CO_(2)+H_(2)O rarr C_(6)H_(12)O_(6)+O_(2)`

Explanation

The three observations are
i) Change of colour
ii) Change of temperature
ii) Evolution of gas
The three information are i) Atmospheric conditions ii) catalyst inolved iii) Physical state of reactants and products Balancing equations
i) `3Fe+4H_(2)O to Fe_(3)O_(4) +4H_(2)`
ii) `6CO_(2) + 6H_(2)O to C_(6)H_(12)O_(6) + 6O_(2)`
OR
a) i) Oxidation : It is defined as process which involves gain of oxygen for example `2Mg(s) + O_(2)(g) to 2MgO(s)`
Magnesium oxygen Magnesiumoxide.
ii) Reduction: It is defind as the process which involves loss of oxygen for example `CuO_((s)) + H_(2)(g) to Cu(s) + H_(2)O(g)` Copper Hydrogen Copper Water
b)i) `2HNO_(3aq)+ Ca(OH)_(2aq) to Ca(NO_(3))_(2aq) + H_(2)O`
ii) `2NaOH_(aq) + H_(2)SO_((4)(aq)) to Na_(2) SO_((4)(aq)) + 2H_(2)O(I)`