Here in this example question, it says calculate KP for the following reaction with KC equal to 0.77 at 570 Kelvin. All right, so here we're given our equation AT2A gases react with 1B solid to produce CD gas plus 3 E gas. All right. The equation that connects KP to KC, remember is
K P = K C β’ R T βNHere we're told that KC is 0.77. R is our gas constant, which is 0.08206. Temperature needs to be in Kelvin, which it's already given in Kelvin, so we plug that in. Now βN, βN is our moles of gases products. So how many moles of gas do we have as products? We have one. We have three more, so that's 4 minus. The moles of gas is reactants. This is a solid, so we're going to ignore it. Here's a gas. There's two. So βN here equals 2.
All right, so then what we're going to do here is we're going to say 77. When we multiply our R&T together, what's found inside is 46.7742. Remember that still being squared? Then we're going to say
46.7742 2 = 2187.825786Take that number, multiply it by 0.77 gives us 1684.625855 as our answer, but we want to do it in terms of sig figs.
77 has two sig figs, 570 has two sig figs. So we're just going to round this up to
1.7 β’ 10 3Here we have our answer to two significant figures, so this would be our final value for KP.