题目

ClO2是一种高效的水处理剂，制备ClO2的化学方程式为 ，X的化学式为 A．Na2 SO4 B．Na2SO3 C．NaHSO4 D．NaHSO3 答案：C 【详解】 据质量守恒定律可知，化学反应前后原子的种类、个数不变，反应前有12个氧原子、2个钠原子、2个氯原子、2个硫原子、2个氢原子，反应后有2个氯原子、4个氧原子，所以一个X的分子中有4个氧原子、1个硫原子、1个钠原子、1个氢原子；X的化学式为NaHSO4，故选C。 in half, in the end, understand.make some mis-takes,  go to college ，   careful ，run away from,organize, be worried about, haveproblems with31.    You can't just _____  the problems.32.    She has very _____  parents. She is so lucky.33.    You must be_____  when crossing the road.34.    There is only one _____  apple,  and we can cut it35.    She _____  in the exam yesterday.36.    They____________   spoken English.37.    Mike studies very hard. He wants_____   next year.38.    Doctors _____  the possible spread of the disease.39.    Ill invite people if you can_____   food and drinks.40.    The man tried several times to start the car, and he succeeded _____  .