Which half reaction occurs at the cathode in this cell? o 2003-> O2 + 2002 +4e-
O O2 + 200, +4e-
> 2003
2H2 + 2003- -
2H2O + 200, +4e
2H20 + 200, +4e--> 2H2 + 2003-

in theory, limestone is composed principally of the compound calcium carbonate - caco3, but in reality this compound is deposited in conditions involving a number of other compounds as impurities so it ends up being a mixture of many compounds.

hope this : -)

tony (lordcaos066)

colorless gas, exhibiting a blue glow when placed in an electric field

b) solid

its a type of rock