What is needed for photosynthesis to take place? Sophie.

光合作用的反应物是什么？苏菲。

Reactants become products and that's that.

反应物变成产物，仅此而已。

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，它们之有够的空供反应物移动通过。

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

但是，叶子如何防止不必的入侵者（如细菌）进入并阻止重的反应物逸出？

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

所以我们有反应物。

We can do that by either measuring the reactants or the products.

我们可以通过测量反应物或生成物来实现这一点。

But what was it about the reagent that revealed the ink?

是什么反应物揭示了墨水？

And gravimetric analysis what we're doing is we're taking two reactants and we're combining those.

我们进行的重量分析是取两种反应物并将它们混合一起。

So here we have the reactants.

所以这里我们有反应物。

And so what are the reactants here?

这里的反应物是什么？

So it's going to convert certain reactants into products.

因此，它将把某些反应物转化为产物。

And so this reaction, one of the reactants are going to be 6 molecules of water.

这个反应中，反应物之一将是 6 个水分子。

How much of that original product or reactant did we have.

我们有多少原始产物或反应物。

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

大写字母代表反应物和生成物，小写字母代表它们的系数。

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

但有时，随着产物变回反应物， 会发生相反的反应。

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

如果你实际上提供了更多的反应物，反应就会朝着那个方向进行更多。

Chemists often know not only the equilibrium constant for a reaction, but also how much of each reactant is available.

化学家不仅知道一个反应的平衡常数，还知道每种反应物有多少可用。

We could measure the products that are created or we could measure the amount of reactants that are being consumed.

我们可以测量生成的产物，或者测量正被消耗的反应物的量。

And the importance of K, which is a measure of the concentration of products to reactants.

K 的重性于它是产物与反应物的浓度的量度。

Now we can get rid of that reactant since it's a solid.

现我们可以除去该反应物，因为它是固体。