资讯

In a mixture, the two ingredients can be separated using physical processes, without chemical reactions. This is because they are not chemically bonded together. A particle diagram of a mixture ...
The periodic table of chemical elements, often called the periodic table, organizes all discovered chemical elements in rows (called periods) and columns (called groups) according to increasing atomic ...
“Topics such as Balancing of chemical equations, acid base and salt, digestion, excretion, circulatory and reproductive ...