# Question #d327a

##### 2 Answers

There are 0.0039 mol of

#### Explanation:

**Step 1.** Calculate

**Step 2.** Calculate the initial value of

We don’t know the initial value of

Let's call it

In this case, we know the equilibrium value of

The equilibrium constant expression is

**Step 3.** Calculate the initial moles of

Here's another way which is related to maths and not chemistry

When we solve for pH we solve like this

Please notice in the calculation I changed pH to 2.63

This is because when I used all the variables including

Here

Solve for b

Let's solve your equation step-by-step.

: Divide both sides by -1.

: Solve Logarithm.

10log(b)=10−2.636(Take exponent of both sides)

b=

b=0.002315

Now

Solve Square Root.

(Divide both sides by 0.00068)

x=0.007881

Now I think you know what to do