identify which element is oxidized and which element is reduced in each of the following reaction and indicate the oxidation states of all atoms before and after the reaction. CH4(g) + 2O2(g) = CO2(g) + 2H2O(g). Zn(s) + 2HCL = ZnCl2(aq) + H2(g).

Question

identify which element is oxidized and which element is reduced in each of the following reaction and indicate the oxidation states of all atoms before and after the reaction. CH4(g) + 2O2(g) = CO2(g) + 2H2O(g).     Zn(s) + 2HCL = ZnCl2(aq) + H2(g).

anonymous · Answer

Always remember OiL RiG. Oxidation is LOSS of electrons/hydrogen and gain of oxygen and Reduction is GAIN of electrons/hydrogen and loss of oxygen. For my classes, it's better to think in terms of electrons, but always remember about oxygen.

That being said, in CH4 + 2O2 = CO2 + 2H2O

The CH4 turns into CO2 by gaining oxygen and O2 turns into H2O by losing oxygen. The first is a reduction and the second is oxidation.

For,  Zn(s) + 2HCL = ZnCl2(aq) + H2(g). The HCl gains a hydrogen to become H2 (reduced), and the Zn gains Cl to become ZnCl2 (reduced).

Think of the half reactions. Hope hat helps!