For the reaction: SO2(g) + NO2(g) ⇌ SO3(g) + NO(g), the equilibrium constant, Kc, is 18.0 at 1200 °C. If 1.0 mole of SO2 and 2.0 moles of NO2 are placed in a 2.0 L container, what concentration of SO3 will be present at equilibrium?

[SO₃] in the equilibrium, will be 0.47 M

Explanation:

First of all we state the equilibrium reaction:

SO₂(g) + NO₂(g) ⇌ SO₃(g) + NO(g)

Intially we have 1 moles of sulfur dioxide and 2 moles of nitrogen dioxide.

The stoichiometry is all 1:1.

During the reaction x amount has reactend, then in the equilibrum I would have

(1-x) moles of SO₂

(2-x) moles of NO₂

and there are formed x moles of SO₃ and x moles of NO

The thing is that, we need molar concentrations, so all the values must be divided by 2L, the vessel volume

Let's make the expression for Kc:

Kc  = [SO₃] . [NO] / [SO₂] . [NO₂]

Kc = x/2 . x/2 / (1-x)/2 . (2-x)/2

Kc = x²/4 / (1-x)(2-x) / 4 → (1-x)(2-x) = 2-x-2x+x² → 2-3x+x²

18 = x²/4 / 2-3x+x²/4 → we cancel the 4 → 18 = x² / 2-3x+x²

18 (2-3x+x²) = x² →  0 = 17x² - 54x + 36

Let's solve the quadratic funtion:

17 = a; -54 = b; 36 =c  → (-b +- √(b²-4ac)) / 2a

(-54 +- √(-54²- 4 . 17. 36)) / 2.36

x1 = 0.95

x2 = 2.22

We take, the first value so the [SO₃] in the equilibrium, will be 0.95/2L = 0.47 M

[SO3] =  0.476 M

Explanation:

Step 1: Data given

Kc = 18.0 at 1200 °C

Number of moles SO2 = 1.0 moles

Number of moles NO2 = 2.0 moles

Volume = 2.0 L

Step 2: The balanced equation

SO2(g) + NO2(g) ⇌ SO3(g) + NO(g)

Step 3: Calculate molarity

Molarity = moles / volume

Molarity SO2 = 1.0 mol / 2.0 L

Molarity SO2 = 0.5 M

Molarity NO2 = 2.0 mol / 2.0 L

Molarity NO2 = 1.0 M

Step 3: Initial concentrations

[SO2] = 0.5M

[NO2] = 1.0 M

[SO3]= 0M

[NO] = 0M

Step 4: Concentration at equilibrium

[SO2] = 0.5 - X M

[NO2] = 1.0 - X M

[SO3]= XM

[NO] = XM

Step 5: Calculate concentrations

Kc = [SO3][NO] / [SO2][NO2]

Kc = 18 = x² / ((0.5- x)(1.0-x)

x = 0.476

[SO2] = 0.5 - 0.476 M = 0.024 M

[NO2] = 1.0 - 0.476 M = 0.524 M

[SO3]= XM = 0.476 M

[NO] = XM = 0.476 M

each  column  of the  table  is called a group. elements in a group share similar properties. groups are  read  from  top  to  bottom. metal. metalloid. nonmetal. solid. liquid. gas. fe. hg. o.  2. 3. 4. 5. 6. 7. 8. 9.  2. beryllium. 9.012. 4.  sodium. 22.990.  11. 3.  magnesium. 24.305.  12.  potassium. 39.098.  19. 4.  calcium. 40.078.  20. i guess  i