1.72/（40+96+36）=1.72/172=0.01mol
2caso4.2h2o==2caso4.h20+3h2o
2 3
失去的结晶水数目=0.01*3/2=0.015NA
答案是对的!生石灰是caso4.2h2o 你等式的左边怎么是2caso4.2h2o 没明白生石灰是caso4.2h2o 你等式的左边怎么是2caso4.2h2o 等式要配平，为此左边是两个生石灰分子