.二氧化碳溶解于水：CO2 + H2O === H2CO3
.生石灰溶于水：CaO + H2O === Ca(OH)2
.氧化钠溶于水：Na2O + H2O ==== 2NaOH
.三氧化硫溶于水：SO3 + H2O ==== H2SO4
.硫酸铜晶体受热分解：CuSO4?5H2O 加热 CuSO4 + 5H2O
.无水硫酸铜作干燥剂：CuSO4 + 5H2O ==== CuSO4?5H2
