I'm having some trouble understanding the calculation of Kp for heterogeneous reactions and finding the number of moles of certain products/reactants in equilibrium..
250.0 grams of solid copper (II) nitrate is placed in an empty 4.0-L flask. Upon heating the flask to 250°C, some of the solid decomposes into solid copper (II) oxide, gaseous nitrogen (IV) oxide, and oxygen gas. At equilibrium, the pressure is measured and found to be 5.50 atmospheres.
a) Write the balanced equation for the reaction.
For my answer, I got 2Cu(NO3)2 (s) → 2CuO (s) + 4NO2 (g) + O2 (g)
b) Calculate the number of moles of oxygen gas present in the flask at equilibrium.
How do you find the number of moles..? Does it have to do with the Initial/Change/Equilibrium table? and if so, that means converting Kp into Kc then, right? Then in the equation Kp=Kc(RT)Δn, how do you find the Δn? Do you include the number of moles for the solids also, or no since solids aren't included in the calculations of Kp?
c) Calculate the number of grams of solid copper (II) nitrate that remained in the flask at equilibrium.
I thought solids weren't included in calculating the Kp, so how do we find the grams..? Or do you convert value of O2 from b into moles of copper (II) nitrate?
d) Write the equilibrium expression for Kp and calculate the values of the equilibrium constant.
Same as in b.. how do you calculate the Δn when there are solids? Do you in/exclude the moles of solids?
e) If 420.0 grams of the copper (II) nitrate had been placed into the empty flask at 250°C, what would the total pressure have been at equilibrium?
It's a solid, so does it even change the equilibrium pressure?..
I know I have a lot of questions, but if you could provide any help that'd be great. Thanks in advance.