- Calcium metal is heated in the presence of nitrogen gas:
Ca + N 2 →Ca 3 N 2 - Solid potassium is added to a flask of oxygen gas:
K + O 2 →KO 2
This reaction is also true for rubidium and cesium. (Note: These are superoxides.) - A piece of solid magnesium, which is ignited, is added to water:
Mg + H 2 O →MgO + H 2
II. Combustion
Substance + Oxygen Gas →Oxide of Element
The usual products are the oxides of the elements present in the original substance in their
highervalence states. When N, Cl, Br, and I are present in the original compound, they are
usually released as free elements, notas the oxides.
- Solid copper(II) sulfide is heated strongly in oxygen gas:
CuS + O 2 →CuO + SO 2
or
→Cu 2 O + SO 2 - Carbon disulfide gas is burned in excess oxygen gas:
CS 2 + O 2 →CO 2 + SO 2 - Methanol is burned completely in air:
CH 3 OH + O 2 →CO 2 + H 2 O
All alcohols (as well as hydrocarbons and carbohydrates) burn in oxygen gas to
produce CO 2 and H 2 O. - Silane is combusted in a stream of oxygen gas:
SiH 4 + O 2 →SiO 2 + H 2 O
III. Metallic Oxide + H 2 O →Base (Metallic Hydroxide) - Lithium oxide is added to water:
Li 2 O + H 2 O →Li++ OH– - A solid piece of potassium oxide is dropped into cold water:
K 2 O + H 2 O →K++ OH–
IV. Nonmetallic Oxide + H 2 O →Acid - Dinitrogen pentoxide is added to water:
N 2 O 5 + H 2 O →H++NO 3 –
Writing and Predicting Chemical Reactions