摘要： 已知热化学方程式: ① C2H2(g) +O2(g) == 2CO2(g)+H2O(l) ΔH1＝-1301.0 kJ•mol-1 ② C(s)+ O2(g) == CO2(g) △H2＝-393.5 kJ•mol-1 ③ H2(g)+ O2(g) == H2O(1) △H3 = -285.8 kJ·mol-1 则反应④ 2C(s)+ H2(g) == C2H2 A. +228.2 kJ·mol-1 B. -228.2 kJ·mol-1 C. +1301.0 kJ·mol-1 D. +621.7 kJ·mol-1
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已知热化学方程式：
① C2H2(g) +
O2(g) == 2CO2(g)＋H2O(l) ΔH1＝-1301.0 kJ?mol-1
② C(s)+ O2(g) == CO2(g) △H2＝-393.5 kJ?mol-1
③ H2(g)+ 
O2(g) == H2O(1) △H3 =" -285.8" kJ·mol-1
则反应④ 2C(s)+ H2(g) == C2H2(g)的△H为（ ）
| A．+228.2 kJ·mol-1 | B．-228.2 kJ·mol-1 |
| C．+1301.0 kJ·mol-1 | D．+621.7 kJ·mol-1 |
已知热化学方程式：
① C2H2(g) +
O2(g) == 2CO2(g)＋H2O(l) ΔH1＝-1301.0 kJ?mol-1
② C(s)+ O2(g) == CO2(g) △H2＝-393.5 kJ?mol-1
③ H2(g)+
O2(g) == H2O(1) △H3 =" -285.8" kJ·mol-1
则反应④ 2C(s)+ H2(g) == C2H2(g)的△H为（ ）
① C2H2(g) +
O2(g) == 2CO2(g)＋H2O(l) ΔH1＝-1301.0 kJ?mol-1② C(s)+ O2(g) == CO2(g) △H2＝-393.5 kJ?mol-1
③ H2(g)+
O2(g) == H2O(1) △H3 =" -285.8" kJ·mol-1则反应④ 2C(s)+ H2(g) == C2H2(g)的△H为（ ）
| A．+228.2 kJ·mol-1 | B．-228.2 kJ·mol-1 |
| C．+1301.0 kJ·mol-1 | D．+621.7 kJ·mol-1 |
已知热化学方程式：
① C2H2(g) +
O2(g) ="=" 2CO2(g)＋H2O(l) ΔH1＝-1301.0 kJ?mol-1
② C(s)+ O2(g) ="=" CO2(g) △H2＝-393.5 kJ?mol-1
③ H2(g)+ O2(g) ="=" H2O(1) △H3 =" -285.8" kJ·mol-1
则反应④ 2C(s)+ H2(g) ="=" C2H2(g)的△H为
① C2H2(g) +
O2(g) ="=" 2CO2(g)＋H2O(l) ΔH1＝-1301.0 kJ?mol-1② C(s)+ O2(g) ="=" CO2(g) △H2＝-393.5 kJ?mol-1
③ H2(g)+ O2(g) ="=" H2O(1) △H3 =" -285.8" kJ·mol-1
则反应④ 2C(s)+ H2(g) ="=" C2H2(g)的△H为
| A．+228.2 kJ·mol-1 | B．-228.2 kJ·mol-1 |
| C．+1301.0 kJ·mol-1 | D．+621.7 kJ·mol-1 |
已知热化学方程式：
① C2H2(g) +
O2(g) ="=" 2CO2(g)＋H2O(l) ΔH1＝-1301.0 kJ?mol-1
② C(s)+ O2(g) ="=" CO2(g) △H2＝-393.5 kJ?mol-1
③ H2(g)+ O2(g) ="=" H2O(1) △H3 =" -285.8" kJ·mol-1
则反应④ 2C(s)+ H2(g) ="=" C2H2(g)的△H为
| A．+228.2 kJ·mol-1 | B．-228.2 kJ·mol-1 |
| C．+1301.0 kJ·mol-1 | D．+621.7 kJ·mol-1 |
O2(g)＝2CO2(g)＋H2O(g) 
H＝－1256
kJ·mol－1。下列说法正确的是（ ）