What is needed for photosynthesis to take place? Sophie.

光合作用是什么？苏菲。

Reactants become products and that's that.

变成产，而已。

Below that is the spongy mesophyll, which have plenty of space in between them for reactants to move through.

下面是海绵状中叶，它们之间有足够空间供移动通过。

But how does the leaf prevent unwanted intruders, like bacteria from getting in and stop important reactants from escaping?

但是，叶子如何防止不必入侵者（如细菌）进入并阻止重逸出？

The products are also breaking back apart into the reactants.

产也分解成。

So over here on the left-hand side we have the reactants.

所以在左侧这里我们有。

So here we have the reactants.

所以这里有。

And so what are the reactants here?

那么这里是什么？

If I raise the temperature, it's like adding a reactant so the reaction will proceed to the right.

如果我提高温度， 就好像添加了一种， 这样就会向右进行。

One particular ratio of reactants to products where the products form at the same rate that they break down.

一种特定与产比例， 其中产形成速率与它们分解速率相同。

That was one of our reactants and it dissolves readily in water, hence the oceans.

那是我们之一， 它很容易溶解在水中， 因很容易溶解在海洋中。

If you actually provide more reactants, you're gonna go more in that direction.

如果你真提供了更多，你就会朝着那个方向走得更多。

So again, it's the product of the products of the product of the reactants and the coefficients become exponents.

同样，它是乘积乘积， 系数变成指数。

But sometimes, there's an opposite reaction that occurs with the products changing back into the reactants.

但有时，随着产变回， 会发生相。

Then, plug in the number of moles for each of our products and reactants.

然后，为我们每种产品和插入摩尔数。

That's why reactants like this are written with a double arrow, indicating that the process runs both directions.

这就是为什么像这样用双箭头书写， 表明该过程是双向进行。

Reconciling the reactants with the products is called equation balancing, and it's a good bit of what stoichiometry is all about.

将与产调和称为方程式平衡，这很好地说明了化学计量学全部内容。

The capital letters stand for the reactants and the products and the lowercase letters stand for their coefficients.

大写字母代表和产，小写字母代表它们系数。

But what if you don't know the standard free energies of formation for the products and reactants?

但是，如果您不知道产和标准生成自由能怎么办？

So even though we can't measure the entropy of reactants or products directly, we can calculate them.

所以即使我们不能直接测量或产熵， 我们也可以计算它们。