+H2C=CH2 →一定条件
+2H2C=CH2 →一定条件
丙烯是三大合成材料的基本原料,可用于合成应用广泛的DAP树脂单体和双酚等有机物,具有重要的工业用途.
Jack was busy last Sunday. His parents were not at home. He walked to the park in the morning. He read English books and did sports there.Then he visited his friend Tom. Tom is his best friend. He is younger and shorter than Jack.They played puzzles together.After lunch, Jack went back home. In the afternoon, Jack cleaned the room and washed the clothes. After finishing these things, his parents got home.
Jack had a nice dinner with his parents. At 10 o'clock, he went to bed.
黄赤交角的大小决定了五带的范围。
下列变化中,属于化学变化的是( )
抛物线y=2(x﹣1)2+3的顶点坐标为( )