Which elements are oxidized?

Which elements are oxidized and which elements are reduced?

• Which elements are oxidized and which ele- ments are reduced in the synthesis of hydro- gen from coal in the reaction H2O(g) + C(s) −> H2(g) + CO(g) ? 1. Neither is oxidized nor reduced because this is not a Redox reaction. 2. Hydrogen is oxidized and carbon is re- duced. 3. Carbon is oxidized and hydrogen is re- duced. 4. Hydrogen is oxidized and oxygen is re- duced. 5. Carbon is oxidized and oxygen is re- duced.

• Answer:

  Which elements are oxidized and which ele- ments are reduced in the synthesis of hydro- gen from coal in the reaction H2O(g) + C(s) −> H2(g) + CO(g) ? 1. Neither is oxidized nor reduced because this is not a Redox reaction. 2. Hydrogen is oxidized and carbon is re- duced. 3. Carbon is oxidized and hydrogen is re- duced. 4. Hydrogen is oxidized and oxygen is re- duced. 5. Carbon is oxidized and oxygen is re- duced. Carbon is oxidized, because the oxidation number, or charge, on C(s) is 0. On the other side the charge is +2, since O = -2, and the sum of charges must be zero. Therefore, the Carbon lost an electron and became positive. Hydrogen is reduced since it went from having an oxidation of +2, since O = -2 and they have to equal 0, to having an oxidation of 0 since it's a lone element, and it got there by gaining two electrons.