4.一定温度下,反应N2(g)+3H2(g)═2NH3(g)达到化学平衡状态的标志是( )
A. | N2、H2、NH3的物质的量不再改变 | |
B. | c(N2):c(H2):c(NH3)=1:2:3 | |
C. | N2与H2物质的量之和是NH3的2倍 | |
D. | 单位时间里每增加1mol N2,同时增加3mol H2 |
3.能与Na反应放出H2,又能是溴水褪色,但不能使石蕊试纸变红色的物质是( )
0 169824 169832 169838 169842 169848 169850 169854 169860 169862 169868 169874 169878 169880 169884 169890 169892 169898 169902 169904 169908 169910 169914 169916 169918 169919 169920 169922 169923 169924 169926 169928 169932 169934 169938 169940 169944 169950 169952 169958 169962 169964 169968 169974 169980 169982 169988 169992 169994 170000 170004 170010 170018 203614
A. | CH3-CH2-COOH | B. | CH2=CH-CH2-OH | C. | CH2=CH-COOH | D. | CH2=CH-COOCH3 |