题目

阅读理解With low temperature, radiation andhigh-energy particles (粒子), the vacuum of space is nothing butharsh. Can you imagine spending six hours walking in apace? Chinese astronautsdid just that on their latest spacewalk.On Aug 20, Chinese astronauts LiuBoming and Nie Haisheng went out on the second spacewalk of the Shenzhou XIImission, according to the China Manned Apace Agency. The pair set up andadjusted equipment, showed their spacesuits and tested the large robotic armand other spacewalk-related devices.Despite the astronauts' skill,spacewalking is a challenging task. Luckily, t31．（2008?义乌市）玛丁啉是一种常见的胃药，可促进胃动力，消除胃胀胃痛等不适症状．已知玛丁啉的化学式为C22H24ClN5O2，请回答：（1）玛丁啉是由______种元素组成的；（2）一个玛丁啉分子中共有______个原子；（3）计算玛丁啉分子中N元素的质量分数．（保留2位小数）