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fwks_phoenix

_{This is easy.. but i have a doubt}

_{form d kp n kc values for formation of ONE mole of ammonia...show me the steps}

tarun_bits

NH4+(aq) + H2O(l) = NH3(aq) + H3O+(l)

Kc = [NH3] [H3O+] / [NH4]...........water will not be considered....

Kp=Kc....as Kp=Kc(RT)n...

there are no gases here....

tka

(1/2)N₂ (g)+ (3/2)H₂ (g) <----> NH₃ (g)

Kc = [products] / [reactants]

= [NH₃]/ [N₂]^1/2[H₂]^3/2

Kp = pNH₃ / pN₂^1/2pH₂^3/2

or using the formula tarun used before,

Kp = Kc (RT)ⁿ

Where ⁿ signifies change in no. of moles of gases.

in this case, it is equal to -1 (1 - (1/2 + 3/2) )

so in this case Kp = (Kc)^-1

@tarun : i think for reactions involving formation of compounds, u must use reactions where it is formed from its constituent elements, and not other compounds

sti

I AGREE WITH TKA. JUST SEE WHETHER THE REACTION IS HOMOGENOUS OR HETEROGENOUS. THEN K IS GIVEN BY PRODUCT OF THE PROUCTS FORMED DIVIDED BY THE PRODUCT OF REACTANTS, RAISED TO SUITABLE POWERS. POWERS CORRESPOND TO COEFFICIENTS IN BALANCED EQUATION. IN THE CASE OF KP PARTIAL PREESURE IS CONSIDERED,IN KC CONCENTRATION IS CONSIDERED. NEGLECT PPS OR [] OF SOLIDS AND GASES.

fwks_phoenix

thanks ppl !!

so it's wrong for the powers to b fractions ?

tka

no, power s can certainly be fractions

akshay.khare91

I think the equation written by tka is wrong
since formation of ammonia is haber's process its equation must be
N₂ + 3H₂ --- 2NH₃_{now write the values of kp and kc ..}

tka

hey, my equation is correct. remember, the question asks the 'formation' of ammonia, and in any question where formation of a product is asked, you must apply the chemical reaction where one mole of product is formed.

fwks_phoenix

thanks ppl.. !! :)

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