In several reactions a colour change indicates the formation of new products. For example, green copper carbonate reacts, when heated, to form black copper oxide and carbon dioxide gas.
The colour comes from a type of carbon and cyanogen, a poisonous gas.
这种颜色来源于一种碳和氰以及一种有毒气体。
3
The red chilli colour product with high color value and high quality was prepared through refining capsicum oleoresin by supercritical carbon dioxide extraction method.