At elevated temperatures, solid silicon reacts with chlorine gas to form gaseous SiCl4. At some temperature, the equilibrium constant for this reaction is 0.30. If the reaction is started with 0.10 mol of SiCl4 in a one-liter flask, how much Cl2 will be present when equilibrium is established?
0.1mol/1L = 0.1M
.........Si(s) + 2Cl2(g) ==> SiCl4(g)
initial..0......0.............0.1M
change....x......2x............-x
equil.....x......2x..........0.1-x
K = (SiCl4)/(Cl2)^2
Substitute from the ICE chart above and solve for x, then 2x for Cl2. Note that solid Si does not appear in the K expression.
ICE techniques
Si(s)+ 2Cl2(g) >> SiCl4(g)
Keq= [SiCl4]/[Cl2]^2
Cl2 SiCl4
2x .1-x concentrations
.3=(.1-x)/(2x)^2
1.2 x^2+x-.1=0
x= (-1+- sqrt (1+.48))/2.4 check that quadratic equation.
x= (-1+sqrt(1.48))/2.4=.09
concentration of Cl2= 2x=.18moles/liter
moles in one liter flask= .18
check all this math.
thank you both
Well, this reaction seems to be quite ambitious, silicon taking on chlorine gas! It's like a battle between the elements. But fear not, equilibrium will be established eventually.
Now, to determine how much Cl2 will be present at equilibrium, we need to use the equilibrium constant (K). In this case, K is given as 0.30. That means for every mole of SiCl4, we'll have 0.30 moles of Cl2.
We started with 0.10 mol of SiCl4, so we'll end up with 0.10 * 0.30 = 0.03 mol of Cl2.
So, when equilibrium is established, there will be 0.03 mol of Cl2 showing up to the party. Time to celebrate chemical equilibrium, the ultimate balancing act!
To determine how much Cl2 will be present at equilibrium, we can use the concept of equilibrium constant and the stoichiometry of the reaction. The equilibrium constant (Kc) is defined as the ratio of the product concentrations to the reactant concentrations, with each concentration raised to the power of its coefficient in the balanced chemical equation.
The balanced chemical equation for the reaction is:
Si + 2Cl2 ⇌ SiCl4
According to the equation, 1 mole of SiCl4 is formed from 2 moles of Cl2. Therefore, at equilibrium, if x moles of Cl2 have reacted, x/2 moles of SiCl4 will be formed.
The equation for the equilibrium constant (Kc) is:
Kc = [SiCl4] / ([Cl2]^2)
Given that Kc = 0.30, and the initial concentration of SiCl4 is 0.10 mol in a one-liter flask, we need to determine the concentration of Cl2 at equilibrium.
Let's assume that at equilibrium, the concentration of Cl2 is 'y'. Therefore, the concentration of SiCl4 at equilibrium will be 0.10 - (x/2).
Substituting the values into the equilibrium constant equation:
0.30 = (0.10 - x/2) / (y^2)
To solve for 'y', we need to find the value of 'x' first. Since the initial concentration of SiCl4 is 0.10 mol, and at equilibrium, x/2 moles of SiCl4 are formed, we have the equation:
0.10 - (x/2) = 0.10 - (0.10/2) = 0.10 - 0.05 = 0.05 mol
Now, we can substitute the value of 'x' into the equation:
0.30 = 0.05 / (y^2)
Rearranging the equation:
(y^2) = 0.05 / 0.30
(y^2) = 0.1667
Taking the square root of both sides:
y = √0.1667 ≈ 0.408 mol
Therefore, when equilibrium is established, approximately 0.408 mol of Cl2 will be present.