The atmosphere is about twenty-percent oxygen and eighty percent nitrogen from Earth's surface to where space begins at one-hundred-twenty kilometers up.

VOA: special.2011.04.06

So, in order to fill our octet, what we do is put two on the nitrogen and two on the carbon.

因此，为了填满我们的“八隅体“,我们需要将两个放到氮上，将另外两个放到碳上。

麻省理工公开课 - 化学原理课程节选

So what we can actually directly compare is the dissociation energy or the bond strength of nitrogen versus hydrogen.

因此实际上我们可以直接进行比较,对氮分子与氢分子的离解能,或键的强度。

麻省理工公开课 - 化学原理课程节选

University of Virginia professor Jim Galloway calls synthetic nitrogen fertilizer a "wonderful invention" because it increased food production.

VOA: special.2011.04.05

It doesn't go all the way to absolutely 100 percent ammoniazero hydrogen zero nitrogen if they were mixed together with the right ratios.

即使按适当比例混合,也不会出现全部氨气,没有氢气和氮气的情况。

麻省理工公开课 - 热力学与动力学课程节选

But he says many parts of the world use too much nitrogen fertilizer, and that harms the environment.

VOA: special.2011.04.05

If we take nitrogen, we've got N2, and we've got one, two, three, four, five.

比如说氮，我们得到了氮气，我们有一个，两个，三个，四个，五个。

麻省理工公开课 - 固态化学导论课程节选

Scientists at the agroforestry center say the use of fertilizer trees can reduce the need for chemical nitrogen by up to three-fourths.

VOA: special.2009.09.01

So, electron promotion does not happen in terms of nitrogen, because it would not increased our number of unpaired electrons.

这里对于氮原子不会有电子激发，因为这不会增加,未配对电子的数目。

麻省理工公开课 - 化学原理课程节选

But the Chinese farmers used six times more nitrogen, and produced almost twenty-three times more surplus nitrogen.

VOA: special.2009.07.28

We see that the radius is shorter, so that means that the nitrogen-nitrogen bond is going to be shorter.

我们看到这个距离更短，这就意味着,氮与氮之间的键应该更短。

麻省理工公开课 - 化学原理课程节选

"For large animals like beef, a very large fraction of the nitrogen that enters the cow's mouth is excreted out the back end."

VOA: special.2011.04.05

4 6 Just as in nitrogen, we get two, four, six here, but now we have two more electrons.

对于氮，我们有，但是现在我们有两个多的电子。

麻省理工公开课 - 固态化学导论课程节选

The list is quite long." So Professor Galloway and other researchers have developed a nitrogen footprint calculator.

VOA: special.2011.04.05

So this is not going to be a favorable process, we're going to find that the electron affinity is actually a negative 7 kilojoules per mole for nitrogen.

因此这并不是一个容易发生的过程，我们会发现氮的电子亲和能,应该是负的，7，千焦每摩尔。

麻省理工公开课 - 化学原理课程节选

There was a new system of liquid nitrogen to keep the pilot cool and to resist the crushing force of gravity at high speeds.

VOA: special.2010.07.07

So, shared electrons are the ones that are shared between the carbon and the nitrogen, so we have 6 shared electrons, and we want to take 1/2 of that.

共用电子是那些在碳和氮之间,被它们共用的电子，那么我们有六个共用电子，然后我们要给它乘上二分之一。

麻省理工公开课 - 化学原理课程节选

The nitrogen calculator is currently designed for people in the United States, Germany and the Netherlands.

VOA: special.2011.04.05

So in terms of nitrogen that starts off with a valence number of 5, again we have 2 lone pair electrons in the nitrogen, and again, we have 6 electrons that are shared.

对于氮来说,我们应该从五个价电子开始，同样，氮也有两个孤对电子，共用电子的个数也一样，是六个。

麻省理工公开课 - 化学原理课程节选

Nitrogen runoffs from farms can create large dead zones, like those in the Gulf of Mexico.

VOA: special.2009.07.28

This is very easy molecule because we know exactly where to put them without even having to think, we only have one option, and we'll make a triple bond between the carbon and the nitrogen.

这个分子非常简单,因为我们知道应该把它们放在哪里,甚至不用去想，我们只有一个选择，我们将在碳与氮之间形成一个三键。

麻省理工公开课 - 化学原理课程节选

Other plants take nitrogen out of the soil, but beans and other legumes replace it.

VOA: special.2009.03.24

So if we take a look at nitrogen here, what you'll notice is we have thre available for bonding, - and we already have our lone pair -- one of our orbitals is already filled up.

如果我们看一下氮原子，我们注意到我们可以成3个键，我们已经有一个孤对-,其中的一个轨道已经被填满了。

麻省理工公开课 - 化学原理课程节选

They take nitrogen out of the air and put it in the soil.

VOA: special.2009.09.01

090 We have 1,090 for carbon, 1000 1,000 for sulfur, 1400 and 1,400 for nitrogen.

碳的是，硫的是，而氮的是。

麻省理工公开课 - 化学原理课程节选

Some experts say the best fertilizers for beets are low in nitrogen.

VOA: special.2010.03.02

Here is the atomic nitrogen, here is the atomic nitrogen and these are the orbitals of molecular nitrogen.

这是氮原子，这是氮原子,然后这是氮气的分子轨道。

麻省理工公开课 - 固态化学导论课程节选

And as it breaks down, it naturally releases nitrogen into the soil.

VOA: special.2010.06.01

So we can put actually all 4 of our extra electrons in between the carbon and the nitrogen.

因此我们可以把这剩下的,四个电子都放在碳和氮之间。

麻省理工公开课 - 化学原理课程节选

So, for instance, this would suggest to us by the way it's written that the hydrogen is attached to the nitrogen and not the oxygen.

因此，比如，这样的写法会提醒我们,这个氢原子是与氮原子成键的，而不是氧。

麻省理工公开课 - 化学原理课程节选