00:01
In this video, we want to write the thermochemical equations for the formation of two compounds.
00:06
For part a, our compound is rubidium chloride rbcl, which in the standard state is going to be a solid.
00:12
And by convention for thermochemical equations, we want the coefficient to be one on this side.
00:20
To complete the equation, on the reactant side, we put the constituent elements in their standard states.
00:26
So that's going to be rubidium, which is a solid because it's a metal.
00:31
And then chlorine exists as a diatomic gas.
00:34
Now, to balance it, we can use fractional coefficients to manipulate the reactant side so that we keep this one on the product side.
00:41
There's one rubidium here and one chlorine.
00:43
One rubidium.
00:44
This is two chlorine, so we need to put a one half.
00:47
And then we can add for part b, the delta h of formation, which you can look up in a table of values or a textbook, and you get that the standard enthalpy of formation is negative 435.
01:01
1 kilojoules per mole, which you include with the equation to make it a complete thermochemical equation.
01:11
All right, for part c, we are considering the formation of lead to nitrate, pbn -032, which is a solid.
01:19
So we have to make it up from lead, nitrogen, and oxygen...