The stress applied to the system is the addition of Cl₂. To offset this stress, some Cl₂ reacts with PCl₃ to produce PCl₅ until a new equilibrium is established.

The net reaction therefore shifts from right to left, that is,

PCl₅ (g) ← PCl₃ (g) + Cl₂ (g)

To work with the Kc expression, we need to convert the grams to moles. Since the volume of the flask is 1 liter, the moles can be expressed as molarity.

For PCl₅:

208.23 g ---------- 1 mol

3.74 g -------------- x= 1.80 x10⁻² mol ⇒ 1.80 x10⁻² M

For PCl₃:

137.33 g ---------- 1 mol

4.86 g ------------- x= 3.54 x10⁻² mol ⇒ 3.54 x10⁻² M

For Cl₂:

70.91 g ---------- 1 mol

3.59 g ----------- x= 5.06 x10⁻² mol ⇒ 5.06 x10⁻² M

Now, taking into account the shift of the equation, we make an ICE chart:

PCl₅ (g) ← PCl₃ (g) + Cl₂ (g)

i) 1.80 x10⁻² 3.54 x10⁻² 5.06 x10⁻²

c) +x -x +1.31 x10⁻² -x

e) 1.80 x10⁻² +x 3.54 x10⁻² -x 5.06 x10⁻²+1.31 x10⁻² -x

Now, we write the Kc formula:

Kc = [PCl₃] [Cl₂] / [PCl₅]

Kc = [ 3.54 x10⁻² -x] [5.06 x10⁻²+1.31 x10⁻² -x] / [1.80 x10⁻² +x]

After working with the expression, we find that x = 1.115.

Therefore, the new concentration of PCl₅ will be 1.133 M.

7 0

3 years ago

Read 2 more answers

I NEED HELP PLEASE, THANKS! :) Draw the Lewis structure for sulfur trioxide, SO3.

butalik [34]

Answer:

Explanation:

Sulfur has valence electron 6 and oxygen has 6*3 = 18 valence electrons. In this drawing, you'll see that sulfur violates the octet rule that is it has more than 8 electrons but it is legal since sulfur is in 3rd period, and elements that fall in 3rd period or more in periodic table can use their d orbitals and others to go beyond the normal "8" electrons in valence shell rule which is octet rule

All the formal charges are minimized...that is everything has formal charge of 0 in this structure which is always encouraged.

Credits to chemistNATE who wonderfully explains it in his video.

6 0

4 years ago