posted by Mariah .
A mixture of 1.441 g of H2 and 70.24 g of Br2 is heated in a 2.00-L vessel at 700 K. These substances react as follows.
H2(g) + Br2(g) arrow 2 HBr(g)
At equilibrium the vessel is found to contain 0.627 g of H2.
calculate their equilibrium concentrations and Kc
mols H2 @ equil = 0.627g/2 = 0.3135
M H2 @ equil = 0.3135/2L = 0.1567M
M H2 begin = (1.441/4) = 0.360M
M Br2 begin = (70.24/159.8) = 0.440M
........H2 + Br2 ==> 2HBr
At equil (H2) = 0.157M; therefore, we know
0.36-x = 0.157 and we solve for x. Use that to calculate each of the equilibrium values, substitute those into the Kc expression and calculate Kc.
Be sure and check (confirm) those numbers. I just ran them one time on my calculator.