A:若向平衡混合物中加入少量W,正、逆反应速率均增大
B:平衡后再加入X,上述反应的△H增大
C:温度不变,将容器的体积扩大一倍,Z的平衡浓度变为原来的1/2
D:2min时,用Y表示的反应速率为0.2mol·L-1·min-1
金属单质和非金属单质在一定条件下可以相互反应,生成相应的____ 或____ 。
如:Fe+S____
2Fe+3C12 ____
3Fe+2O2 ____
过点P(1,3)作圆O:x2+y2=1的两条切线,切点分别为A和B,则弦长|AB|=( )
四个悬挂着的带电泡沫小球,相互作用的情况如图所示.那么D球可能( )
阅读下列短文,从每小题的三个选项中选出最佳选项。
It's autumn. It's cool and windy. Charlie is flying a kite in the park. His father is watching(观看).The kite is flying high(高) in the sky. They are happy. Look! The kite is not in the sky now. Where is it? Oh, it's in a tree. Charlie is sad. Charlie jumps and jumps. The tree is tall but he is short. He cannot get(拿到) the kite. Charlie's father is not very tall but he is clever(聪明的). Look, he is on a car. He can get the kite for Charlie. Charlie is happy.