题目

如图是某汽车尾气净化装置中发生反应的微观示意图。下列说法正确的是（ ）A. 该反应中，Z是由Y分解生成的B. 一个Y和W分子中均有11个电子C. 参加反应的X与生成的Z的质量比为9：7D. 化学反应前后，催化剂的质量和性质一定不变 答案：【答案】C【解析】由反应的微观示意图可以看出，反应物是NH3和NO两种分子，生成物是N2和H2O两种分子，所以化学反应方程式为：6NO+4NH35N2+6H2O。A、由微粒的构成可知，X、Y都含有氮原子，不能确定Z是由Y分解生成的，故A不正确；B、由微粒的构成可知，Y和W分子分别是氨分子和水分子，一个Y和W分子中均阅读理解。We have two new students in our school. They are Mary and Kate. They look the same (看上去一样), but they are not twins. Kate is an English girl. She is twelve. She is in Class Two. She likes her dog. Mary is an English girl, too. She is eleven. She is in Class Five. She likes football. Mary and Kate are our good friends. We all love (爱) them.【1】Kate is from ________. （ ）A. China B. England C. America【2】Mary ________ Kate. （ ）A. looks like B. looks at C. looks【3】Mary likes ________. （ ）A. her cat B. football C. her dog【4】Kate and Mary are in the same ________. （ ）A. row (排) B. class C. school【5】Kate and Mary are ________. （ ）A. the same age (年纪) B. not the same age C. twelve