ap chem help

Test Preparation AP Test Preparation
1

<p>Hi i need help on this problem i know it is easy, but dafdsafdasf i just can aasdfasfdsa get it.
anyway
NH4HS(s)<---->NH3 (g) +H2S (g)</p>

<p>Some solid NH4HS is placeni an evacuated vessel at 25 ? C. after equilibrium is attained the total pressure inside the vessel is found to be 0.659 atm. some solid nh4hs reamains in the vssel at equilibrium. Calculate KP at 25 ?c.
i know i have to use kp=kc(rt) ^delta n
Kc= [Nh3] x [h2s], but how do i get the partial concetrations of that ?
r= the constant, t = 25+273= 298 ? k,
n= 0-2. </p>

<p>OR</p>

<p>i can do this</p>

<p>Kp= pNH3 x pH2S</p>

<p>but how do i get the partial pressures from the total pressures :S
help wuld be appreaciated</p>

2

<p>I know this is late, but in case you're still wondering....</p>

<p>Since the vessel initially only has solid, at equilibrium the two gaseous products will be present in equal amounts (according to the coefficients of the balanced equation.) Since the amounts are equal, the pressures are equal. Therefore pNH3 = pH2S = 0.659/2</p>