我們常用的有：
1.化合物中,各元素化合價(jià)代數(shù)和為零
2.溶液質(zhì)量=溶質(zhì)質(zhì)量+溶劑質(zhì)量
3.溶液的溶質(zhì)質(zhì)量分?jǐn)?shù)=溶質(zhì)質(zhì)量/（溶質(zhì)質(zhì)量+溶劑質(zhì)量）*100%
即：溶液的溶質(zhì)質(zhì)量分?jǐn)?shù)=溶質(zhì)質(zhì)量/溶液質(zhì)量*100%
4.溶解度=溶質(zhì)質(zhì)量/溶劑質(zhì)量*100g
5.溶液的溶質(zhì)質(zhì)量分?jǐn)?shù)=溶解度/溶解度+100g
6.蒸發(fā)原溶液質(zhì)量一半的溶劑,溶質(zhì)質(zhì)量分?jǐn)?shù)提高一倍
7.加入原溶液質(zhì)量一半的溶劑,溶質(zhì)質(zhì)量分?jǐn)?shù)減半
8.同種溶質(zhì),質(zhì)量相同,但溶質(zhì)質(zhì)量分?jǐn)?shù)不同的兩種溶液相混合時(shí),
混合后的溶質(zhì)質(zhì)量分?jǐn)?shù)=二者質(zhì)量分?jǐn)?shù)和的一半
9.化學(xué)方程式計(jì)算