00:01
So for this problem, we're going to use hess's law.
00:09
So let's write the final equation that we are looking for.
00:13
Lead reacts with oxygen form lead oxide.
00:17
So we have two equations given to us, and let's figure out how we can get the final one from manipulating these two.
00:24
So first of all, let's get the reactants on the reactant side and the products on the product side.
00:31
Flip equation one.
00:32
When we flip equations, we have to negate the delta h value.
00:36
So here i've done that.
00:38
Now multiply that equation by two.
00:40
Because you can see that in our final equation, we have two lead oxide, and then we need two lead oxide on the right.
00:48
So then for the second equation, we do not do anything.
00:55
Okay, so now we will add them together, cancel off species with the same phases on both sides.
01:01
So let's see what we end up with.
01:03
So we cancel out this carbon, cancel out carbon monoxide.
01:09
And then we end up with our final equation, which is exactly what we are looking for...