题目

据有关专家介绍，用醋酸（CH3COOH）蒸气对空气进行消毒可以有效地预防流感。请计算：（1）醋酸的相对分子质量为_____。（2）30g的醋酸中含氧元素的质量为_____g。 答案：【答案】（1）60；（2）16g【解析】（1）醋酸的相对分子质量为12+1×3+12+16+16+1=60；（2）30g的醋酸中含氧元素的质量为：30g××100%=16g.—Her eyes were tears as she looked happily at her son.—Yes,she must be very happy.A. covered with B. agreed with C. filled with D. took up