00:01
There are multiple steps involved in this question.
00:05
To solve for delta g for the chemical reaction, given two chemical reactions and their equilibrium constants, we first need to use hess's law to figure out how we can combine those two chemical reactions to get the overall reaction.
00:21
Then, after combining those two reactions, we need to look at their equilibrium constants and combine, use those equilibrium constants.
00:31
To determine the equilibrium constant of the overall reaction.
00:36
Then, once we have the equilibrium constant of the overall reaction, we can calculate delta g for the overall reaction.
00:43
The overall reaction is h2o plus 1 .5 .02 goes to h202 at 600 degrees cell, or 600 kelvin.
00:52
We want to calculate delta g.
00:54
I don't want to give it all away here at once.
00:57
So the two chemical reactions for which we have information are h2, plus o2 goes to h202, with an equilibrium constant of 2 .3 times 10 to the 6.
01:10
Then we have 2h2 plus o2 goes to 2h2 with an equilibrium constant of 1 .8 times 10 to the 37.
01:18
In order to combine these two chemical reactions to get this overall reaction, we need to reverse the second reaction and divide by 2, or multiplied by 1 half.
01:29
When we do that, we get this reaction here, and what is its new equilibrium constant? well, if we divide a reaction by two or multiply it by one -half, we need to raise this k -value to one -half.
01:45
Also, if we reverse the chemical reaction, we need to take the reciprocal of the k -value, so we need to do both.
01:53
The new k -value will be one over the original k -value raised to the one -half.
02:02
We'll then cancel what's common to both sides, and we do get the overall reaction up above...