Definition of equilibrium constant Kp for gas phase reactions, and how to calculate Kp from Kc.
Log in gizem.cetin.usa 8 years agoPosted 8 years ago. Direct link to gizem.cetin.usa's post “Why do we not include liq...” Why do we not include liquids and solids in equilibrium expressions? What do you mean by "their concentration is equal to 1"? • (19 votes) Alex Wrede 8 years agoPosted 8 years ago. Direct link to Alex Wrede's post “The concentration of the ...” The concentration of the solids never changes, as its density remains the same. Regarding liquids, adding or removing liquids has an insignificant effect on the concentration of the system, as the system is in an aqueous solution. Yes, the liquids do change the concentration, but not by a measurable amount. It's like adding another fish to the sea, making pretty much no difference to the concentration of fish in the ocean (35 votes) Mushahid Osman 8 years agoPosted 8 years ago. Direct link to Mushahid Osman's post “In example 2, how do you ...” In example 2, how do you know that you are finding the constant in terms of bar and not atm? • (7 votes) kausik sivakumar 8 years agoPosted 8 years ago. Direct link to kausik sivakumar's post “It is because the Univers...” It is because the Universal Gas Constant R=8.314 is substituted and pressure calculated by using this will give you the answer in terms of barr caroxxwu 6 years agoPosted 6 years ago. Direct link to caroxxwu's post “For the equation Kp = Kc(...” For the equation Kp = Kc(RT)^(delta N), shouldn't there be two instances in which Kp = Kc? First, when delta N = 0 (mols of product gas = mols of reactant gas); second when temperature T is the exact reciprocal of constant R or when R*T = 1 (if R = 0.08206 L*atm*mol^(-1)*K^(-1), T = 1/0.08206 K)? What is the significance of Kp = Kc? • (7 votes) Clara I-W 8 years agoPosted 8 years ago. Direct link to Clara I-W's post “Can anyone explain why Pr...” Can anyone explain why Pressure does not change the equilibrium constant for a reaction but temperature does? • (3 votes) Ernest Zinck 8 years agoPosted 8 years ago. Direct link to Ernest Zinck's post “The equilibrium constant ...” The equilibrium constant is a constant. (7 votes) AJ 7 years agoPosted 7 years ago. Direct link to AJ's post “For the ICE Table, how do...” For the ICE Table, how do we know that the Change has +2x and +x? I mean, why did we choose plus instead of minus? • (4 votes) RogerP 7 years agoPosted 7 years ago. Direct link to RogerP's post “With the ICE table, you i...” With the ICE table, you initially assume that the reaction is entirely on the left, with water but no hydrogen or oxygen gases. Then, as the reaction proceeds, hydrogen and oxygen are formed, which are written as +2x and +x atm in the "change" line. If you used minus signs, that would indicate that the gas concentrations were decreasing as the reaction moved towards equilibrium, which is not the case. Adit Khokar 8 years agoPosted 8 years ago. Direct link to Adit Khokar's post “in the formula Kc = Kp * ...” in the formula Kc = Kp * (RT)^n • (2 votes) ŞΣΔşђ ĐŗДġΦЇđ 8 years agoPosted 8 years ago. Direct link to ŞΣΔşђ ĐŗДġΦЇđ's post “but you cant arbitrarily ...” but you cant arbitrarily double the moles of reactants or products in a particular BALANCED reaction. (5 votes) Lucian Rex 7 years agoPosted 7 years ago. Direct link to Lucian Rex's post “When the do the PV=nRT, s...” When the do the PV=nRT, shouldn't the final equation be P=nRT/V, not P=(n/V)RT? • (1 vote) yuki 7 years agoPosted 7 years ago. Direct link to yuki's post “The two expressions P=nRT...” The two expressions P=nRT/V and P=(n/V)RT are the same. The second one is written specifically to separate out the expression n/V, which is equal to the concentration. This helps emphasize the relationship between concentration and the ideal gas equation. (5 votes) apndolby297 8 years agoPosted 8 years ago. Direct link to apndolby297's post “As in example 3, why are ...” As in example 3, why are we taking the partial pressure of water in liquid form as 1, why not any other value (say less than 1)? • (2 votes) ŞΣΔşђ ĐŗДġΦЇđ 8 years agoPosted 8 years ago. Direct link to ŞΣΔşђ ĐŗДġΦЇđ's post “adding or removing liquid...” adding or removing liquid makes a very negligible difference in the pressure of the system. (3 votes) Sneha Shrestha 7 years agoPosted 7 years ago. Direct link to Sneha Shrestha's post “why it is difficult to fi...” why it is difficult to find equilibrium constant at room temperature • (3 votes) Anshari Hasanbasri 6 years agoPosted 6 years ago. Direct link to Anshari Hasanbasri's post “Why is it difficult? You ...” Why is it difficult? You just need to plug in the room temperature for T in Kp=Kc(RT)^(delta n) (assuming you were to find Kp from Kc of the molecules) (1 vote) Swarna 7 years agoPosted 7 years ago. Direct link to Swarna's post “In example 3, what does N...” In example 3, what does N/A in the ICE table indicate? • (2 votes) RogerP 7 years agoPosted 7 years ago. Direct link to RogerP's post “N/A is a common abbreviat...” N/A is a common abbreviation for "Not applicable". (2 votes)Want to join the conversation?
If you want to calculate in terms of atm then use R=0.0820
If you change a pressure, all the pressures change so that their new values will give the same value for the equilibrium constant.
if we use double the reactants then the difference b/w the number of moles will also get double Kc will change
all values for the moles should be calculated using a balanced equation simplified to its lowest form.
increasing quantity of reactants will not change the value of kc either, kc always is a constant for a given temperature.
but it has no effect on difference in moles for a balanced reaction.
(correct me if i'm wrong)
you can assume it as 1 without changing the answer.
at least for calculation purposes
besides taking any value apart from 1 will unnecessarily increase the difficulty of your calculations.
