1.6 Chemical Equilibria, le Chateliers Princile And Kc

Question 1

Define the term dynamic equilibrium

Answer 1

The rate of the forward reaction is equal to the rate of the reverse reaction

Question 2

Give an essential condition for an equilibrium mixture

Answer 2

Equilibrium occurs in a closed system (where reactants and products cannot escape)

Or

Macroscopic properties do not change with time

Question 3

State Le chatelier’s principle

Answer 3

If a system at equilibrium is disturbed, the equilibrium moves in the direction that tends to reduce the disturbance

Question 4

Slide 8

Question 5

Slide 10

Question 6

Slide 13

Question 7

What effect does a catalyst have on the position of equilibrium?

Answer 7

No effect

Question 8

What condition affects the value of Kc

Answer 8

Temperature

Question 9

For the reaction below, deduce an expression for Kc

2[A] + 3[B]+ [C] ⇌ [D] + 4[E]

Question 10

Deduce the units for the value of Kc for

[D]X[E]^4 /[A]^2+ [B]^3

Answer 10

Mol^-1 dm^-3

Question 11

What type of system is Kc relevant for?

Answer 11

Homogeneous systems in equilibrium

Question 12

What does Kc being greater or lesser than 1 suggest for the position of equilibrium?

Answer 12

Greater than 1 = over to the right

Lesser than 1 = over to the left

Question 13

What effect does decreasing the temperature in an endothermic reaction have on Kc.

Answer 13

Kc decreases

Question 14

What effect does increasing the temperature in an endothermic reaction have on Kc.

Answer 14

Kc increases

Question 15

What effect does decreasing the temperature in an exothermic reaction have on Kc.

Answer 15

Kc increases

Question 16

What effect does increasing the temperature in an exothermic reaction have on Kc.

Answer 16

Kc decreases