(1)12*2+3*1+12*1+1+16=56
(2)C:H:O=12*3:4:16=9:1:4
(3)16/56=0.2857
(4)3C/C2H3CHO=36/56=0.64286 C=112g*0.64286=72g
24+3+12+1+16=56
36:4:16=9:1:4
16/56=28.6%
112*36/56=72
(1)相对分子质量:56
(2)C:O:H=9:4:1
(3)16/56=28.6%
(4)碳元素的质量分数为:12/56
所以,112克中含碳=112×36÷56=72克
忘了