Oxidations and reductions

Oxidation of nonmetals by $O_2$

The reaction of carbon with oxygen:

Carbon burns with a yellow flame and sparks producing carbon dioxide, a colourless and odourless gas. $C$ $+$ $O_2$ $\longrightarrow$ $CO_2$

The reaction of white phosphorous with oxygen:

White phosphorous burns with very intense yellow flame producing a thick white smoke of phosporous(V) oxide. $P_4$ $+$ $5O_2$ $\longrightarrow$ $ P_4O_{10}$

The rection of sulfur with oxygen:

Sulfur burns with a blue flame producing sulfur dioxide ( = sulfur(IV)oxide ), a colourless gas with a suffocationg odour. $S_8$ $+$ $8O_2$ $\longrightarrow$ $ 8SO_2$

Oxidation of metals by $O_2$

The reaction of magnesium with oxygen:

Magnesium burns with a dazzling white flame producing magnesium oxide, a white solid substance. $2Mg$ $+$ $O_2$ $\longrightarrow $ $2MgO$

The reaction of sodium with oxygen:

Sodium burns with a yellow flame producing sodium oxide, a white solid substance. $4Na$ $+$ $O_2$ $\longrightarrow$ $ 2Na_2O$

Reactions of oxides with water

Oxides of nonmetals

The oxides of nonmetals will cause the aqueous solution of bromothymol to change to yellow. Acids are produced: $CO_2$ $+$ $H_2O$ $\longrightarrow$ $H_2CO_3$ (product: carbonic acid) $P_4O_{10}$ $+$ $6H_2O$ $\longrightarrow $ $4H_3PO_4$ (product: phosphoric acid) $SO_2$ $+$ $H_2O$ $\longrightarrow$ $ H_2SO_3$ (product: sulfurous acid)

Oxides of metals

The oxides of metals will cause the aqueous solution of bromothymol to change to blue. Bases are produced: $MgO$ $+$ $H_2O$ $\longrightarrow $ $Mg(OH)_2$ (product: magnesium hydroxyde) $Na_2O$ $+$ $H_2O$ $\longrightarrow$ $ 2NaOH$ (product: sodium hydroxyde)

Reduction of metal oxides by $H_2$

The reaction of copper(II) oxide with hydrogen

Heated in a stream of hydrogen, the black powder of copper(II) oxide turns to red copper powder. Water has been produced which condenses on the cold tube wall. $CuO$ $ +$ $ H_2 $ $\longrightarrow$ $ Cu$ $ + $ $H_2O$

The reaction of iron(III) oxide with hydrogen

Heated in a stream of hydrogen, the red powder of iron(III) oxide (= rust) turns to black iron powder. Water has been produced which condenses on the cold tube wall. $Fe_2O_3$ $ + $ $3H_2 $ $\longrightarrow $ $2Fe $ $+$ $ 3H_2O$

Oxidation and reduction

Oxidation and reduction are opposite processes. Oxygen is one example of an oxidant Hydrogen is one example of a reductant