Sunday

February 1, 2015

February 1, 2015

Posted by **Swaastikaa** on Sunday, March 25, 2012 at 3:11am.

H2(g)+I2(g)--->2HI(g) Kc = 54.9

Initially,the system had 2.50 moles of HI.What is the moles of H2 at equilibrium?

Can Dr.Bob check if my steps are correct?

My solution:

Initially,the concentrations of H2 & I2 are 0,whereas concentration of H1 is 2.50mol/5L = 0.50 mol/L .At equilibrium,the concentrations of H2 & I2 are assumed to be x,whereas concentration of HI is 0.50-2x

Using equlibrium constant equation with respect to concentration,

Kc = [HI]^2/[H2][I2]

54.9 = (0.50-2x)^2/x.x

Since 2x is assumed to be negligible,therefore the equation above further simplified to :

54.9 = (0.50)^2/x.x

x^2 = (0.50)^2/54.9

x = 0.06748 mol/L = [H2] = [12]

Therefore moles of H2 at equilibrium is

0.06748 mol/L X 5L = 0.337 mol

Is my steps and answer correct? Thank you in advance

- Chemistry -
**DrBob222**, Sunday, March 25, 2012 at 12:57pmThe set up looks good but you can't neglect the 2x. I ran through it quickly and obtained 0.266 for mols H2 by solving the quadratic.

- Chemistry -
**Swaastikaa**, Monday, March 26, 2012 at 4:04amBut why I can't ignore the 2x? Could Dr.Bob please explain?

**Answer this Question**

**Related Questions**

Chemistry - The following reaction has an equilibrium constant of 0.020 at a ...

Chemistry (Equilibrium) - Consider the following equilibrium system at 900°C: ...

AP Chemistry - For the system 2SO2(g) + O2(g) <--> 2SO3 (g), change in ...

chemistry - Initially, there are 33 moles of A and 0 moles of B. How many moles ...

chemistry - The following reaction has an equilibrium constant of 0.50 at a ...

chemistry - A study of the system, H2(g) + I2(g) == 2 HI(g), was carried out. Kc...

Chemistry - A reaction mixture of 4.0 mL of 0.002 M SCN- and 5.0 mL of 0.002 M ...

Chemistry(Please help, thank you!) - A study of the system, H2(g) + I2(g) == 2 ...

CHEMISTRY - for the reaction system H2 + X2 <->2HX Kc = 24.4 at 300 K a ...

Chemistry - For the system, H2(g)+X2(g) <-> 2HX(g) Kc=24.4 at 300K. A ...