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When two substances are heated, they combine to form a compound.
A compound ion, the main source of nitrogen for plants.
Colourless, odourless, heavier-than-air gas. Necessary for the photosynthesis of plants.
One of the oxoacids of nitrogen. Colourless, moderate acid with a pungent odour, that...
Purple and wine red flowers can be used as pH indicators.
A colourless, odourless gas, an important component of the atmosphere, indispensable to...
One of the allotropes of phosphorus.
A yellow-green toxic gas with a strong odour, one of the halogens.