A、是CO2和H2在3分钟时浓度相等,则速率分别为
=2.00mol/L?1.25mol/L 3min
=0.25/mol?min与0.75mol/L 3min
=3.00mol/L?0.75mol/L 3min
=0.75mol/L?min,速率不同,故A错误;2.25mol/L 3min
B、首先从图象可看出,反应物为H2.CO2(浓度降低),生成物为CH4O;再从浓度的变化量的最简单整数比可确定它们的系数为3.1.1,结合质量守恒原理,可知生成物中还有1molH2O;再根据反应热求出△H=-1113.64KJ÷
=-49.0KJ/mol,热化学方程式为:CO2(g)+3H2(g)?CH4O(g)+H2O(g)△H=-49.0KJ/mol,故B正确;1000g 44g/mol
C、平衡常数K=
=1.07,故C错误;0.75×0.75
0.753×1.25
D、降温平衡向正反应方向移动,平衡常数增大(>1.07),不可能为0.8,故D错误.
故选B.