Question

肼(N2H4)是火箭发动机的一种燃料，反应时N2O4为氧化剂，反应生成N2和水蒸气．已知： N2(g)＋2O2(g)N2O4(g) ΔH＝＋8.7 kJ·mol－1 N2H4(g)＋O2(g)N2(g)＋2H2O(g) ΔH＝－534 kJ·mol－1 下列表示肼和N2O4反应的热化学方程式，正确的是
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A．	2N2H4(g)＋N2O4(g)3N2(g)＋4H2O(g) ΔH＝－1 076.7 kJ·mol－1
B．	N2H4(g)＋N2O4(g)N2(g)＋2H2O(g) ΔH＝－1 076.7 kJ·mol－1
C．	2N2H4(g)＋N2O4(g)3N2(g)＋4H2O(g) ΔH＝－542.7 kJ·mol－1
D．	2N2H4(g)＋N2O4(g)3N2(g)＋4H2O(g) ΔH＝－1 059.3 kJ·mol－1

Answer 1

答案：A
解析：

N2(g)＋2O2(g)N2O4(g)　ΔH＝＋8.7 kJ·mol－1① 　　N2H4(g)＋O2(g)N2(g)＋2H2O(g)　ΔH＝－534 kJ·mol－1② 　　②×2－①得2N2H4(g)＋N2O4(g)3N2(g)＋4H2O(g)　ΔH＝－1 076.7 kJ·mol－1，故选A．