00:01
So this is a hess's law problem.
00:03
What that means is that we're going to use the enthalpy of known reactions to determine the enthalpy of an unknown reaction.
00:09
We're provided the unknown reaction for the target reaction, and we can use the two reactions above that have standard amplies for that reaction.
00:18
So first things first, i would identify things that are in the target reaction that we see in one and only one of those reactions.
00:25
So i'm going to start with the a .s .3.
00:27
I see 2 -s -o -3 on the reactant side, or on the product side, it needs to be on the reactant side.
00:34
So we're going to flip this whole reaction, and to get it up to 8, we're going to multiply everything by 4.
00:41
So when we flip it and multiply it by 4, we get 8 -s -o -3 gas yields 8 -s -o -2 gas plus 402 gas, and the delta h, we need to flip the sign, so it's going to be positive 197 .8.
01:04
And we need to multiply it by 4.
01:08
So when we do that, we end up with the delta h of 791 .2 kilojoules.
01:14
So then we're going to do the same thing with the other reaction, because we see we have 8s solid, and we have 1s solid in that top reaction.
01:23
So we're going to multiply this whole reaction by 8...