题目

Gold fever     In 1848, when gold was discovered in California, John Sutter was already one of the wealthiest people in America.  34    Sutter built a fort (要塞) there, and soon he had 12,000 head of cattle (牛) and hundreds of workers.     By the mid-1840s, more and more Americans were coming to California.  35  He saw them as part of his new kingdom (王国). However, he had no idea that this would destroy his dream some day.     At the beginning of 1848, Sutter sent James Marshall and about twenty men to the American River to build a sawmill.  36  Later he wrot18．工业上利用N2和H2可以合成NH3，NH3又可以进一步制备联氨（N2H4）等．（1）火箭常用N2H4作燃料，N2O4作氧化剂．已知：N2（g）+2O2（g）=2NO2（g）△H=+67.7kJ•mol-1N2H4（g）+O2（g）=N2（g）+2H2O（g）△H=-534.0kJ•mol-1NO2（g）?$\frac{1}{2}$N2O4（g）△H=-26.35kJ•mol-1试写出气态联氨在气态四氧化二氮中燃烧生成氮气和气态水的热化学方程式：2N2H4（g）+N2O4（g）=3N2（g）+4H2O（g）△H=-1083kJ•mol-1．（2）联氨--空气燃料电池是一种碱性燃料电池，电解质溶液是20%～30%的氢氧化钾溶液．该电池放电时，正极的电极反应式为O2 +4e-+2H2O=4OH-．（3）在300℃时，改变起始反应物中氢气的物质的量对反应N2（g）+3H2（g）?2NH3（g）△H＜0的影响如图所示．①请在图中画出400℃时对应的图象．②在a、b、c三点中，H2的转化率最高的是a（填字母）．（4）硝酸工业生产中的尾气可用纯碱溶液吸收，有关的化学反应为：2NO2+Na2CO3═NaNO2+NaNO3+CO2，NO+NO2+Na2CO3═2NaNO2+CO2．若在标准状况下有NO、NO2的混合气体（不考虑N2O4）恰好与50mL 1． 0mol•L-1的Na2CO3溶液反应完全，且生成NaNO2和NaNO3的物质的量的比为4：1，则在混合气体中NO气体的体积分数为多少？（请写出计算过程）