2010年10月1日,我国在西昌卫星发射中心成功发射“嫦娥二号”。嫦娥二号火箭推进器以联氨(N2H4)为燃料、过氧化氢为助燃剂。已知下列各物质反应的热化学方程式为
N2H4(g)+O2(g)=N2(g)+2H2O(g);ΔH1=-533.23 kJ·mol-1
H2O(g)=H2O(l);ΔH2=-44 kJ·mol-1
2H2O2(l)=2H2O(l)+O2(g);ΔH3=-196.4 kJ·mol-1
则联氨与过氧化氢反应的热化学方程式可表示为( )
| A.N2H4(g)+2H2O2(l)=N2(g)+4H2O(l);ΔH=+817.63 kJ·mol-1 |
| B.N2H4(g)+2H2O2(l)=N2(g)+4H2O(g);ΔH=-641.63 kJ·mol-1 |
| C.N2H4(g)+2H2O2(l)=N2(g)+4H2O(l);ΔH=-641.63 kJ·mol-1 |
| D.N2H4(g)+2H2O2(l)=N2(g)+4H2O(g);ΔH=-817.63 kJ·mol-1 |
What I need is_____ book that contains ______ABC of oil painting.
| A.a; 不填 | B.the; 不填 | C.the; an | D.a ; the |
Jenny nearly missed the flight______ doing too much shopping.
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The CDs are on sale! Buy one and you get ______ completely free.
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Progress______ so far very good and we are sure that the work will be finished on time.
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Charles was alone at home, with_______ looking after him.
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