分子平均自由程是指分子每两次连续碰撞之间，一个分子自由运动的平均路程。

A . ['https://assets.asklib.com/psource/2016071713152316030.jpg 和https://assets.asklib.com/psource/2016071713152742735.jpg 都增大B .https://assets.asklib.com/psource/2016071713152316030.jpg 和https://assets.asklib.com/psource/2016071713152742735.jpg 都减小C .https://assets.asklib.com/psource/2016071713152742735.jpg 减小而https://assets.asklib.com/psource/2016071713152316030.jpg 增大D .https://assets.asklib.com/psource/2016071713152742735.jpg 增大而https://assets.asklib.com/psource/2016071713152316030.jpg 减小

A . 胸腺嘧啶 B . 腺嘌呤 C . 胸腺嘧啶或腺嘌呤 D . 胞嘧啶

A . 1 B . 2 C . 3 D . 4

A .https://assets.asklib.com/images/image2/2017051110385098774.jpg 和https://assets.asklib.com/images/image2/2017051110380742552.jpg 都增大B . 和https://assets.asklib.com/images/image2/2017051110385098774.jpg https://assets.asklib.com/images/image2/2017051110380742552.jpg 都减小C .https://assets.asklib.com/images/image2/2017051110385098774.jpg 减小而https://assets.asklib.com/images/image2/2017051110380742552.jpg 增大D .https://assets.asklib.com/images/image2/2017051110385098774.jpg 增大而https://assets.asklib.com/images/image2/2017051110380742552.jpg 减小

A . ['https://assets.asklib.com/psource/2015110116090848342.png 和https://assets.asklib.com/psource/201511011609344439.png 都增大1倍B .https://assets.asklib.com/psource/2015110116090848342.png 和https://assets.asklib.com/psource/201511011609344439.png 都减为原来的一半C .https://assets.asklib.com/psource/2015110116090848342.png 增大1倍而https://assets.asklib.com/psource/201511011609344439.png 减为原来的一半D .https://assets.asklib.com/psource/2015110116090848342.png 减为原来的一半https://assets.asklib.com/psource/201511011609344439.png 而增大1倍

A . 增大，不变 B . 不变，增大 C . 和都增大 D . 和都不变

A . ['https://assets.asklib.com/psource/2016071712020182603.jpg 增大，但https://assets.asklib.com/psource/2016071712020830684.jpg 不变B .https://assets.asklib.com/psource/2016071712020182603.jpg 不变，但https://assets.asklib.com/psource/2016071712020830684.jpg 增大C .https://assets.asklib.com/psource/2016071712020182603.jpg 和https://assets.asklib.com/psource/2016071712020830684.jpg 都增大D .https://assets.asklib.com/psource/2016071712020182603.jpg 和https://assets.asklib.com/psource/2016071712020830684.jpg 都不变

A . 活化分子 B . 活化能 C . 活性大分子 D . 活泼小分子

A . ['https://assets.asklib.com/psource/2015102709053931679.jpg 和https://assets.asklib.com/psource/2015102709054145245.jpg 都增大一倍B .https://assets.asklib.com/psource/2015102709053931679.jpg 和https://assets.asklib.com/psource/2015102709054145245.jpg 都减为原来的一半C .https://assets.asklib.com/psource/2015102709053931679.jpg 增大一倍而https://assets.asklib.com/psource/2015102709054145245.jpg 减为原来的一半D .https://assets.asklib.com/psource/2015102709053931679.jpg 减为原来的一半而https://assets.asklib.com/psource/2015102709054145245.jpg 增大一倍

A .https://assets.asklib.com/images/image2/2017051115145513283.jpg 增大，https://assets.asklib.com/images/image2/2017051115140643714.jpg 不变B .https://assets.asklib.com/images/image2/2017051115145513283.jpg 不变，https://assets.asklib.com/images/image2/2017051115140643714.jpg 增大C .https://assets.asklib.com/images/image2/2017051115145513283.jpg 和都https://assets.asklib.com/images/image2/2017051115140643714.jpg 增大D .https://assets.asklib.com/images/image2/2017051115145513283.jpg 和都https://assets.asklib.com/images/image2/2017051115140643714.jpg 不变

A . 减小而不变 B . 减小而增大 C . 增大而减小 D . 不变而增大

A . 增大，但不变 B . 不变，但增大 C . 和都增大 D . 和都不变

A . ['https://assets.asklib.com/psource/2016071713390535263.jpg 和https://assets.asklib.com/psource/2016071713390918762.jpg 都增大1倍B .https://assets.asklib.com/psource/2016071713390535263.jpg 和https://assets.asklib.com/psource/2016071713390918762.jpg 都减为原来的一半C .https://assets.asklib.com/psource/2016071713390535263.jpg 增大1倍而https://assets.asklib.com/psource/2016071713390918762.jpg 减为原来的一半D .https://assets.asklib.com/psource/2016071713390535263.jpg 减小为原来的一半而https://assets.asklib.com/psource/2016071713390918762.jpg 增大1倍

A . 升高 B . 降低 C . 不变

在一个标准大气压下,氮气分子的平均自由程为6.0×10-8m,而目前实验室能够获得的极限真空约为<img src='https://img2.soutiyun.com/ask/2020-05-11/958045652421033.png' />. (1)当温度不变时,在该极限真空条件下,氮气分子的平均自由程为多少？ (2)若温度T= 27℃ ,在两种大气压强条件下,氮气分子的密度各为多少？

A．燃料活化能的大小，与其反应能力无关 B．活化能越大的燃料，其反应能力就越强，即使在较低的温度下也容易着火和燃尽 C．活化能越小的燃料，其反应能力就越强，即使在较低的温度下也容易着火和燃尽 D．活化能越小的燃料，其反应能力就越弱，需要在较高的温度下才会着火