Gypsum is hydrated calcium sulfat,CaSO4·xH2O.A residue of 5.65g of anhydrous calcium sulfate is obtained by heating 7.15g gypsum.Determine the empirical formula of gypsum不用翻译……尤其是拿翻译软件翻译的……这个太。咳咳要得是怎么写这个题~

加热7.15gGypsum（石膏）可一得到5.65gcalcium sulfate （硫酸钙）
CaSO4·xH2O=CaSO4+xH2O
5.65g divided by 136g/mol equals to 0.042mol
7.15g divided by 0.042mol equals to 172.1 g/mol
172.1g/mol minus 136g/mol equals to 36.1 g/mol
36.1g/mol divided by 18g/mol equals to 2
sothe empirical formula of gypsum is CaSO4·2H2O
看英文其实和看华文没多大区别。

翻译:
石膏是水合的钙sulfat，硫酸钙·xH2O. 无水硫酸钙5.65g残
滓通过加热7.15g石膏获得。 确定石膏实验式

write out the equation first,assume that the number of water is x.
CaSO4.xH2O(136+18x)=CaSO4(136)+xH2O(18x)
无水硫酸钙和x水和硫酸钙的差量为7.15-5.65=1.50g,所以水的质量就是1.5g
列方程
136/5.65=18x/5.0
解得x=2.0
the expirical formula of gypsum is CaSO4.2H2O