I see that the equilibrium concentration of O_2

is 0.0750 molar. I see that the equilibrium concentration of O_2

is 0.0750 molar.

So now I have some information about my initial concentrations is 0.0750 molar.

So now I have some information about my initial concentrations

and one of my equilibrium concentrations. So now I have some information about my initial concentrations

and one of my equilibrium concentrations.

Know that of SO_3 we can assume starts at 0.

Now what we want to look at is the change row.

We get this information bu looking at the balance chemical equation.

What we can look at, is first I am going to look at oxygen because it has a coefficient of 1. We get this information bu looking at the balance chemical equation.

What we can look at, is first I am going to look at oxygen because it has a coefficient of 1.

I am going to say I lose oxygen

and I am know I am going to lose oxygen because I only have

reactants present, so the only way for this reaction

to proceed is towards the formation of SO_3.

When I say I am going to lose oxygen, I am going to say

X amount of oxygen, or X moles of oxygen.

When I look my balanced equation I see 2 in front of SO_2. X amount of oxygen, or X moles of oxygen.

When I look my balanced equation I see 2 in front of SO_2.

So I know the change in SO_2 is going to be 2 times

the amount of oxygen, because I have a coefficient of 2 for SO_2

and coefficient of 1 for oxygen.

I also know my change is going to be negative,

because just like with my oxygen I am going to lose SO_2 I also know my change is going to be negative,

because just like with my oxygen I am going to lose SO_2

and we are going to form SO_3.

We cannot lose any SO_3 because we do not start with any SO_3. and we are going to form SO_3.

We cannot lose any SO_3 because we do not start with any SO_3.

So when I look at the SO_3 it also has a 2 in front of it, so I know the change is going to be

2 x, or twice as much oxygen as I lose.

It is going to be a positive value because we are gaining SO_3.

Now I can write my equilibrium row

and put the values in that I know.

So I have 0.100 -2x and put the values in that I know.

So I have 0.100 -2x

in this case I already know the equilibrium concentration of oxygen.

So I do not need to put anything there.

And then I look at the SO_3

2x for the equilibrium concentration of SO_3.

But I need to find the value of X

because in order to find the value of K_c But I need to find the value of X

because in order to find the value of K_c

I need to know that value

to be able to plug in actual concentrations here for 2x and 2x.

But what I do know is that my equilibrium concentration of oxygen is

0.0750.

I know that is going to equal to the sum of the initial row

and the change row

so I have 0.100 - x.

I can rearrange.

I can actually solve for x, and what I end up with is X equals

0.0250.

Now, what this is going to let me do is plug this value for x

but into my equilibrium table, my ICE table Now, what this is going to let me do is plug this value for x

but into my equilibrium table, my ICE table

and solve for the actual concentration

of SO_2 and the actual concentration of SO_3 at equilibrium.

Once I know those actual concentrations I can plug them into my law of mass action.

and calculate the K_c value.