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So by using the tabulated data, we can really determined heats of formation for most reactions that you might contemplate, OK?
所以，使用这些表格,我们就能确定大多数,你可能碰到的反应的生成热？
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That's the set up. We're going to run the reactants, the reaction. The reactants are going to turn into products.
这就是我们的装置，我们要进行反应,让反应物变成生成物。
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There's not actually chemical covalent bonds that are formed but it's a non-covalent interaction, usually dominated by hydrogen bonding.
所以配体和受体之间不生成共价键,这是一种非共价化合反应,它们通常以氢键相联
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And we haven't talked about reactions at all yet, so you don't need to worry about the specifics of that exactly, but just that if you have this negative change in energy, you have a more stable product than you do reactant.
当然我们还没有开始讨论反应，所以你不用担心它的细节是怎么样的，你只需要知道，如果能量的变化是负值，那么你将得到一个比反应物更稳定的生成物。
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And, this involves the reaction of titanium tetrachloride with magnesium to form magnesium chloride plus titanium And, this was invented in 1937 by W. J. Kroll.
四氯化钛和镁,反应生成氯化镁和钛,1937年W。J。克劳尔发明了这个方法。
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You could run the reaction, take solid iron gaseous oxygen, form iron oxide, measure the heat of formation of it, tabulate it.
你可以进行一个反应,用固态铁和氧气生成氧化铁，测量它的生成热，列成表格。
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That's the important message, delta H of formation of the products, minus delta H of formation of the reactants.
去反应物的生成焓，这,是个重要的信息，生成物的生成焓,减去反应物的生成焓。
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It's a state function. If we know the enthalpy of the products minus the enthalpy of the reactants, right. It's a state function.
如果我们知道生成物的焓减,去反应物的焓的值,它是个态函数，原则上我们可以做到。
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Well, I need to write the reaction that forms that compound from it's elements, right?
我需要写出从元素单质生成,这种化合物的反应，对吧？
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In other words, I've got reactants, and I've got products. What's delta H of reaction?
换句话说，我有了反应物,我有了生成物？
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In other words, we choose a convention for the zero of entropy, so that then we can write entropies of products and reactants always referring to the same standard state.
换句话说，我们选择了一个,焓零点的约定，这样我们,就可以总是相对于同样的标准,状态写出生成物和反应物的焓。
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There is some mixture of them.
实际情况是生成物与反应物的混合。
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We can tabulate them. We can know them, and then when we have reactions that inter-convert different compounds, we can calculate the heat of reaction is just the difference between the heat of formation of the reactants, and the heat of formation of the products, right.
种化合物的生成热，可以把它们列成表,可以认知它们，而当我们要处理，在不同化合物间转变的反应时,我们只要计算反应物和,生成物的生成热之间的不同,就能计算出反应热。
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A reaction performed by one enzyme creates a product that stimulates another enzyme that creates a product, and stimulates another enzyme, and through this cascade of reactions you amplify and carry the signal forward.
一种酶催化生成的产物会活化另一种酶,而它催化的产物又能激活其他酶,催化反应生成另一种产物,通过这层层反应,信号被放大,并不断向前传递
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It's delta H of formation of the products minus delta H of formation of the reactants.
反应的△H是多少？,它就是生成物的生成焓减。
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How many moles of gas are there in each case, in reactants and products? If that changes, of course you know that the pressure in there is going to change at constant volume if the amount of gas in there is changing.
在反应物和生成物中，各有多少摩尔的气体？,如果它发生了变化,当然在等体条件下，如果气体的总量,发生了变化，压强也会发生变化。
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When delta G is zero, you know, it doesn't mean that you've got all of one side, all reactants and zero products or all products and zero reactants.
当dG等于零的时候，化学反应并不处在任何一边，例如全部都是反应物没有生成物,或者全部都是生成物而没有反应物。
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Right? In other words I've got the stoichiometric coefficients in there and the values, and I'm subtracting the reactants from products -1652kJ/mol wind up with minus 1652 kilojoules per mole.
对吧？换句话说这里我用了化学,计量系数和生成热的值，从生成物中减去反应物,最后得到。
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And if I do that then I can find out the change in enthalpy of this reaction. It's just going to be the heat of formation of these three moles of water, minus the heat of formation of the iron oxide. OK.
我就能得到这个,反应的焓的变化,它就是三摩尔水,的生成热，减去氧化铁的,生成热，好。
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Of course, the cyclic steps that we've taken to do this apply not just for breaking down reactants and product into the elements in their standards states, but of course we could also look at whole sets of reactions and write cycles as well, right.
当然，我们这里用的循环的,步骤不仅仅在把生成物,和反应物拆成其标准状态下,的元素时有效,我们也可以研究整个一系列,反应并写出相应循环。
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